Welcome everybody.

This is a..

Another bonus lecture.

And it's Christmas.

Well almost Christmas as I'm recording this.

So Merry Christmas.

If you celebrate that if you don't and you live in the United States at least it's usually a day or

a week off.

So that's a good thing.

No matter what.

So I've been thinking about what to do for this bonus lecture and I was gonna do another ISP 32 some

more programming stuff.

However two things happen.

A new student mentioned how he was you know in the field of electronics and he was talking about a test

he did one time and he had a kind of reverse engineering schematic.

So he thought that kind of learning how to read schematics would be something interesting.

All right.

Now right before I read that e-mail a couple days beforehand a friend of mine who's in other kind of

game developer he used to be like at Sun Microsystems the sun Java and so forth the inventors of Java

they had a kind of gaming division.

He was one of the evangelists or directors there of the gaming division.

So anyway he's big into games and retro games and to play some of these game systems on your LCD monitor

makes him look really really really bad.

Right.

So we remember most of these game consoles from the 80s and 70s and 80s these retro game consoles they

were played on CRTC right cathode ray tubes like up here on Wikipedia and the cathode ray tube works

in a completely different fashion than an LCD.

Now depending on your age you may have never seen a cathode ray too.

Right.

So if you're fairly young you may have never actually seen one working right you may have seen pictures

of a cathode ray tube or a CRT how it operates is it generates electrons it boils electrons off a filament

and then these electrons are accelerated.

All right.

With these various coils towards the screen and the screen is covered with phosphate coating that when

the electron strikes it it gives off light and there's three different phosphorus red green and blue

in various patterns depending on the TV manufacturer.

There's three different electron guns that are generating these electrons and then firing these electrons

being accelerated and the electron gun sweeps from left to right top to bottom and generates the image

on the screen.

The phosphorus screens look really really really good.

They look really rich and they have a nice look to them.

And then when you try to play these games from the 80s on a new LCD the signals coming out of the game

systems are NTSC signals NTSC they're not B.J. signals they're not HDMI they're not digital they're

analog in nature and they're encoded as an analog signal.

So the LCD TV has to decode this extract it this analog signal and then render it on the LCD it just

looks really bad.

All right.

That said so a lot of people my friend included what they would like to do is use a CRT to play their

old video game systems but instead of using an NTSC signal and of course if you can ever you know again

if you have no context not even know what I'm talking about but I'll get to it if you have one of these

old consoles and it puts out a composite NTSC signal.

That signal is still analog in nature and it's encoded and it's not digital so it means it has to be

decoded the pixels the color the sync all has to be decoded and it's you know noisy.

So the image is still not that good because of the NTSC encoding.

However some of these game consoles and these older ones and even some of the newer ones have direct

red green and blue output like a VBA right.

Like a standard VBA output or monitor that red green and blue is is pure data so it's not encoded it's

not mixed.

And then there's maybe some sync signals.

And again I'm going to tell you I'll tell you how this stuff works in a second.

There's some sync signals so now if you could take that RG v signal and get it into one of these CRT

TS get around the NTSC built in hardware that decoding then you get a much better picture.

So the point is my friend said Hey can you look at I have this TV I want to convert it from a normal

CRT that takes NTSC signals right and composite NTSC signals and can you convert it so that it would

work within our GV signal or tell me how to convert and tell me what I need to do.

And then he showed me some videos of other people doing on internet.

I've done this for many years myself I've converted these

CRT so they take our TV signals directly because it's a much better picture.

Right.

So anyway in doing that I had to start looking at the schematics for this particular TV set.

So let me go here and I'm going to show you.

So here is my friend's TV.

So it's this sharp TV and you can see it's a normal CRT TV it's got a cathode ray tube in there.

Right.

And if you start scrolling through here what I'm looking for is the schematic.

So this is the service manual so for engineers.

So if you scroll through here and you can see it's got all these kind of technical pieces of information

really really cool.

And this is what the service guys would get.

All right.

And then here is you know the chassis layout kind of showing from a top view there is these different

PCV.

P.S. P.W. be a P.W. VH P.W. b b etc. These are showing these different things.

Now when you.

So when you're looking at schematics.

Now again.

So the whole idea of this lecture is we're just going to kind of look at a schematic and there's lots

of different kinds of schematics for example the schematics that we have been generating in the course.

Right.

Our kind of electrical engineering embedded schematics embedded Engineering Schematics.

So we have a certain way of drawing things and doing things.

If you look at schematics from engineers that design television sets the way they draw some things are

a little bit different.

They use you know some different kind of techniques and the way that they their assumptions and their

conventions are a little bit different but more or less you can kind of figure it out if you look at

schematics electrical cement schematics say from a power engineer right who builds power plants those

will start to be a little bit confusing or if you look at even electrical schematics from electricians

they'll be kind of harder because they'll have symbols and you just won't be familiar with.

And for example you know my air conditioning I don't know if I mentioned this maybe in a couple of videos

I mentioned my air conditioners you know got two of them in one of them blew out and I was looking at

it and looking at the schematic and you're looking at the schematic trying to figure out what these

different symbols are.

Right.

And you know you stare at it you stare at it after why was there to figure out this thing supposed to

be like a capacitor this thing supposed to be like a coil this thing supposed to be ground.

This is a switch.

This is a relay but they've got their own way of doing things.

That said as we look at this schematic this is really good experience because it kind of gets you to

be able to follow signals and then kind of drill down from kind of a block level a high level to a schematic

level.

So that said when you get like a TV schematic or kind of an appliance schematic a lot of times you'll

see a block diagram.

All right.

So and that's what we see right here.

All right I'm going to zoom in just a little bit.

So here's the block diagram of this TV and you know showing different things right here.

So you know what does this for example.

Well that's a speaker.

So that's a little coil and a little symbol that is a speaker and you can see sound output.

So this is the built in speaker in the TV set.

One of them and there's probably another one someplace else.

All right.

So we would look through this schematic.

And so my friend his whole goal is he.

He basically says hey I've got this TV and it's got a video input.

Right.

And that video input takes NTSC and I'm going to talk about that in a minute signal and I want to figure

out can I somehow connect red green and blue or an RG v signal into this TV because I know you can do

it because I've seen other people do it on YouTube.

Can you show me how to do that and show me where to connect and all that kind of stuff.

So that's what we're trying to figure out here.

So this is a big project not something we're going to do in an hour right.

So I'm but I'm just gonna kind of show you some of my thought process and this is what engineers do.

So this might be a job.

So he's my friend right.

I'm just going to kind of show him where to kind of put this and tell him some things to watch out for

and all that.

But if someone were to say Hey Andre I want you to do this project for me I'd say well it's gonna take

maybe 20 hours or 40 hours or 60 hours or 80 hours 100 hours whatever it's going to take.

I would come up with a proposal then I.

This would be a job and I would sit here figure it out I would design it make a prototype build it test

it verify it and deliver it.

OK.

If someone wanted this maybe they want to make a product out of it.

I don't know.

But in this case we're just looking.

OK.

So here's the block diagram.

And so you know the first thing you do is just kind of look at it at first it's kind of confusing.

So we know that this P.W. b h in this P.W. B.

These are boards and then there's this P.W. b a board.

So this is the big main board and these are two smaller boards.

And we know that because here is kind of these representations of these mechanically so there's these

three boards.

This is a pretty simple board.

This P.W. B dash H board.

And this means absolutely nothing.

This is probably an acronym for something printed printed circuit printed something it's probably printed

something board with these different letters H and A.

But a lot of times things just are made up but you can see this just has two connectors and it has this

H.A. here which I'm not sure what this is.

Okay.

And a lot of things you're not sure what they are H.A..

I don't know maybe heat sink.

I'm not sure.

I have no idea.

I'd have to look at it and this is what we've got to do right.

So there's a speaker.

This is where the inputs are.

So on a TV set again I'm sure you've seen audio and video inputs here they are and this is the composite

input that takes NTSC video.

All right.

And then if we were in Europe and whatnot then you know those TVs work on Powell right.

There's NTSC PAL and seek them where the old analog standards.

Right.

And so here in the United States obviously we have NTSC signals and NTSC TV's and most TV will still

take these signals even the modern ones with HDMI.

All right then we've got this other board right here which you know so two CRT cathode.

So this is like a driver board.

This is this is the actual board that's connected to the yoke of the CRT.

And let's kind of go back here so this whole thing is called the yoke and this is the whole CRT assembly.

These are the deflection plates celebrated plates.

And so one of these boards can X right here.

All right.

So one of those boards can X right there that's this board I believe.

All right.

OK.

Now we're looking down through here so now we're getting stuff that looks more familiar to us right.

We've got this is a chip and you can see when you zoom in here a little bit.

Excuse me.

I'm going to be coughing in this and that a little bit.

I've got horrible allergies right now.

My face probably looks all puffy in my eyes maybe watering so I've got allergies like cedar fever here

in Austin Texas we have these cedar trees and this stuff is hugely allergic.

I am hugely allergic to it.

So it's just stopped right now.

It's like sound stuffed up and all that.

So I will try and edit out most of my allergy attacks but we'll see what happens.

All right.

So we see this.

I see right here and this is I see to a one in a saying P.I. FSF Chroma video deflection.

So these are obviously abbreviations of something so P.F. stands for something SPF Chroma means color

video deflection.

That's a video deflection circuitry.

So this chip drives the the display.

This drives the actual CRT part.

OK.

So this is good.

So we know that.

And then this you know all these various signals here in these kind of block diagrams they represent

either a chip or chips or analog components.

So this for example Q tool one I f preamp the stands for intermediate frequency preamp S.F. tool one.

This is a sort Well saw me and saw two.

So this is some kind of sawtooth generator.

I see.

For one it's probably a transistor could be a transistor effect you know and you got it.

You just kind of look through these things now of course this is TV technology.

So I don't expect you to understand it but you're just looking through these blocks and trying to figure

these things out see what's going where.

So here's the driver chip that drives this.

And then over here let me see if get my little hand here.

Yeah.

Then over here there's another I see I see 2001 now this is interesting.

And this is system control and it's connected to let me back up a little.

It's connected to this chip here.

It's got RG be coming out of it going into this chip so that we're going to swing back to that.

It's got this mute control here which is kind of going up.

So we've got this mute going up here to this sound chip.

So wait a minute.

Here's a.

This is the speaker.

This thing right here.

So I see three five to this says are sound probably means right sound right channel sound all right.

And then there's a signal here which I bet you this one right here is sound.

I see it's audio out.

So there it is audio out right there.

So this is the right speaker now.

I said there's probably a left speaker but on this one there may not be.

Nope.

So there's a single speaker.

Here's the output.

And then one of these is a mute control to turn the speaker off and then the other one is this line

right here that I'm following is a delay driver.

So this this is relay driver and then it's a relay regulator.

This looks like it's power.

This looks like it's power going into this chip.

So anyway that's what you do.

You got to just start tracing things for what you're kind of interested in.

So again a lot of these things and I don't even know what they stand for because I have to look and

figure out what these guys mean by these abbreviations a lot of times you have to figure it out.

Right now I do a lot of video hardware I've built a lot of video systems a lot of video hardware graphics

chips all those kinds of things and obviously game consoles so I do a lot of NTSC Powell V-J RG all

those kind of things I mess with many many many countless TV sets.

So I've gone through this but every single one of those different things in it.

So that you're not quite sure what these little symbols mean like AT&T OK.

This is a this is a switch right here.

So there is an audio here there's an external audio and there's a TV audio and this is a switch.

And so this AT&T right here I have no idea what that means but this is some kind of switch here.

So it allows you to switch between these two things.

Eighty could mean attenuation.

Right.

And right here why in so in TV parlance Y means Luma or the brightness signal.

Right.

And that's why I.

So this means Y in Luma in luminosity in and c is the chroma or color signal seeing so you know you

kind of figure out what you know and and you got to kind of figure this stuff out right.

All right.

But again we don't really care about that we're going to come back and figure out how we would convert

this into an RG view monitor.

I just want you to kind of look at it just for a minute here.

So this chip here kind of is this controller chip.

This is this video driver chip and then we can see things here.

Now in this schematic again it's a block diagrams you're not going to really see many parts but we can

see hey there's a transformer right.

There's some kind of transformer.

This is these are coils.

Right.

These are inductor coils.

There's some stuff going on here.

Right.

More so this is another transformer.

So this is a it's got multiple primaries and multiple secondaries.

Right.

And this these two lines that means the core of the transformer so it's got a Common Core and there's

primaries and secondary.

That's interesting.

Some more these are really.

So there's a coil right there's the core.

And then here's the armature.

So these are relays right there is our line coming in there's our power coming in right there there's

a fuse symbol.

So you kind of can make your way through this thing right.

Just slowly and surely kind of what's the whole you know global view of things right now after you've

kind of figured that out and I'm going to tell you the only thing we're going to care about is these

two chips from what we're going to try and figure out.

Then we go down and we start looking at the actual schematics all right.

And then if you're a TV service guy these way forms right here represent what things should be doing

at different test points.

So if you're testing the TV and you're trying to debug it you're trying to fix the thing.

That's what this manual is for.

You need to be able to see hey this horizontal signal is number one and it should be point nine six

volts peak to peak.

This if you go this is signal 12 it should be five point four.

It should look like this et cetera all these should look like this.

So if something says at this test point you should see a number 19.

It better look like this one and it better be 260 volts speak to peak.

OK.

All right.

Now here is the schematic.

So here's where things get finished as close up doesn't help us any.

So here's a schematic attempt to zoom out a little bit and yeah there it is.

OK.

So that's the whole of it.

And it's go back in.

So there is that icy tool when there is that video driver chip that we were looking at up and the other

one right.

That's the the top chip the video driver now some place is going to be that video controller chip and

it may be on it's probably going to be on another page.

I'm going to zoom out.

We do.

Yeah.

So here it is right here so there's that video controller chip.

So there it is right there.

You can see it's very complicated.

But now we know every single one of these parts.

Right.

What's that.

There's a transistor right there.

What kind of transistors that.

That's an NPM transistor.

These are capacity.

This is a capacity.

These are resistors right.

Here's another capacitor.

So this symbol right here this is an electrolyte a capacitor and this is the way they do it with these

lines.

But they put the plus and minus let you know it's electrolyte.

There's resistors.

We do all that.

That's easy.

More resistors more capacitors.

What's this thing right here look like.

So we look here and it's got an input it's got a ground it's got an output.

This says K K 7 0 4 5 a reset.

Not sure what that is we'd have to look that up.

It's a three terminal device.

It could be some kind of regulator or something else but we would just look that part up and we're going

to see how to do that.

Also here is a.

An I see.

So this is I see 21 to 1.

And then so it's telling us this is an E from and then you can see here's the eye squirt see inputs.

So I've talked about that a little bit maybe.

You know again this is not a embedded course.

This is not of course about microprocessor microcontroller design it's about electronics basic analog

digital.

So we're not talking we haven't talked about protocols like I scored C or spy or you arts and all that.

But anyway this is a I squared c e problem electrically a reasonable program will read only memory.

So that's a memory.

And then this right here I'll tell you is a processing chip.

I've looked this up and we'll we'll go look this up.

This is a processing chip this is a processor right here all right.

And see is there anything else interesting over here we can see some of this nastiness all this analog.

A lot of analog electronics.

But again we know what all this stuff is there are diodes right.

So this is a kind of bridge vector fire situation going on here.

There's that multi top transformer we saw.

Let's see right here FP 7 co 2 This might be a fair idea.

This might be how they draw their right bead.

And again you know we have to look at the parts list and say what is FP 7 0 2 is that a fair right beat.

But that may be how they draw.

So FBI 7 0 2 for example there is a Shockey diode right Xena diode there's a Xena diode right and this

is an eight.

It looks like it's an eighteen point five volt Xena diode to keep that clamp this over voltage protection

signal at eighteen point five.

That's what that must be.

Let's see.

And anyway and then here's our little ground symbol.

All right.

These little ground symbols.

So this is us going through this schematic and kind of looking at things.

All right.

And then a and c and then here's another one showing what's connected to that actual CRT.

This is all these signals that are connected to it for red green and blue.

And this is the actual driver's section you can see red green and blue ground nine ball.

This is nine volt B means usually bias 9 volt bias and this kind of is what's driving these drivers

are.

So we're not going to mess with red green and blue there.

I mean actually show you a different place you're going to do it.

All right.

So before we dive into this we've been talking about 20 minutes before we dive into this completely

and kind of look how we would want to do this.

What I want to do is I want to just talk briefly about the whole idea of CRTC and let's close ups.

So definitely go on wikipedia and look up cathode ray tube I'd like you to do that and just pass to

this and kind of read this a little bit.

You know it's very interesting and it's you just get an idea of what's going on here.

Right.

So go go through there and kind of see the first CRTC rule actually invented in the late eighteen hundreds

believe that or not.

I think it was eighteen ninety eight or something like that if you look through here I bet you will

say it but yeah unbelievably old technology.

Yeah.

Cathode rays were discovered by John wheel him wheel him high tariff in 1869 1869 and then yeah.

Crooks show that could be deflected by magnetic field in 18 1890 like crucial crucially deflected magnetic

fields 1897.

Yeah so you got to read this but that's just crazy to think about.

These people were doing things in late eighteen hundreds how nutty is that this is advanced technology

you're talking about subatomic particles you know crazy crazy.

So take a look at that then the other thing I want to talk about NTSC signal.

And again if you're not interested in CRTC and NTSC and video signals and all that you know you can

just not care about this too much but the whole idea engineering is about a lot of times learning something

new because a client wants you to do something so you may have a situation where someone wants you to

make a video converter from NTSC or BGR RGA or this or that to HDMI to whatever it is you're gonna to

go read this stuff.

So it's good experience to learn how to look this stuff up and understand it.

So NTSC stands for the national television system committee and yeah like 1950 it was formed.

Yeah the first standard was developed in 1941 and then the second in 1953.

So this is the standards very very old.

And so here's the whole thing NTSC is you know basically was developed in 41 the kind of one that we

used as 1953.

So this is 50 you know 70 years roughly old 70 years old and it's still not bad.

I mean it's amazing that it was invented that long ago I kind of read through here but that the technical

details that I want to get to and like I said there's NTSC and then over in Europe there's Powell which

is a French word.

It stands for something French which I can never remember and then there's Sikhism which is sequential

sequential color in memory I believe.

And then Powell will look that up in a second because I can't remember it even though I'm half French.

I should know what it stands for.

But what I want to show you is let's see if we can see a signal here I'm sorry for scrolling and there's

very there's versions others version of above it.

Let's see let's see.

Do they say what pal is here with the acronym is no.

Yeah.

Phase alternating line.

I feel like there's a another something French I can't remember anyway.

Phase alternating line.

Yeah a palace similar to NTSC it's maybe a little bit better in some ways right.

But I want to show you the signal and no.

OK so let's go here NTSC signal.

No spec let's go to images Yeah.

So this is.

And you'll see this if you read my book my black art a video game console book or my design your own

video game console book that comes with this course which is basically just the copy version of it.

You'll see figures like this inside of my book here.

And let's go here and open this up and of course it did that because it's a transparent image.

All right let's go grab another one.

Let's see.

This one's not bad.

OK.

And so what.

What are you even looking at here now.

This is an analog signal so again I don't expect you to understand this.

This takes this took a long time for me to understand and study and all that.

So I don't expect to understand it five minutes but this right here what this represents is a video

line.

So this is the signal of one single line of video in an NTSC signal.

All right.

What's called a base fan signal now NTSC is is modulated.

So you've got channel to channel 3 Channel 4 Channel 5 and the base signal is modulated on a carrier.

Forget about all that.

This is just the base signal.

So this is the base signal before modulation.

So this represents one single line of pixels across the screen.

Then in addition to this there's line line line so there's draws all these lines on the screen and there's

a vertical sync signal that tells the electron going to go back up to the top and do it all again.

Now in each horizontal line there's different portions of it.

So this right here is the horizontal sync.

And at the beginning of every line there's a sync and a signal happens that goes in the negative direction.

This tells the TV receiver hey I want you to take that electron gun and bring it back to the left point

of the screen because we're gonna draw a new line.

All right so this electron beam beams red green and blue are scanning across the screen constantly.

This says bring it back and synchronize to the left side of the screen.

And I want to draw a line.

All right.

Then it says OK great.

Then how did they encode color.

Now this is one of the most interesting things NTSC.

It's also laughingly called never the same color twice how color is encoded.

It's not red green and blue.

How color is encoded is as a phase angle.

All right.

So basically what happens here is there's this thing called the color versus this little oval.

Really looks like this.

So this is a zoomed in version here.

And what it is.

It's about eight to 10 little pulses of of a certain frequency right in that certain frequencies the

color versus frequency.

All right.

And the color versus frequency is what three point look that up get the actual three what is a three

point four or five megahertz color burst and you can see it's been a while since I've done old fashioned

NTSC even though I've done an enormous amount of it three point 5 7 9 5 4 5 megahertz is the color of

this frequency.

OK.

So you create a sine wave of three point three point five seven right megahertz and he put out eight

to ten pulses of that.

Then you put that on this.

On top of the signal.

Right.

What's going to happen is that TV receiver is looking it's got a filter looking for this three point

five seven megahertz signal.

The second it sees that signal.

It tries to lock onto it and it's got eight to 10 different waves right.

Eight to 10 different samples to lock onto it.

So it starts trying to lock onto it.

And finally it locks onto it.

So now it's in synchronicity with the signal.

All right.

Now here's the interesting part.

Then we come over here a little bit more of this in this whole thing happens in sixty three point five

microseconds.

So we'll talk about that in a second.

Now we start drawing pixels so this is where the pixels get drawn.

You got fifty two point six microseconds to draw pixels in this time you're going to draw the pixels

on the screen and there's about depending on what you want to do about one hundred and sixty pixels

or color clocks that you can control the color of.

So on a normal SD TV old school CRT you only had about one hundred and sixty pixels across that screen.

Believe it or not that you could control the color of you could change the luminosity at a much higher

frequency but or much higher pixel rate.

But the color was only about 160 pixels.

That's it.

Now how the color is encoded is like this is as you are drawing the Loomis signal.

So this is basically this lose signal as you're drawing each one of these pixels here.

The phase angle of that Luma signal compared to the phase angle of this color burst depending on the

phase of it relative to this reference frequency depending on the phase of it.

That'll be the color and then as you go around 360 degrees you would get different colors.

I know this is super crazy isn't it.

So if we say color burst circle maybe.

Let's see.

That didn't help us.

Let's see NTSC color burst.

Circle Yeah.

Here we go and so that what this is showing is at face angle zero.

Right.

You get kind of a blue and then as you rotate around and change the face angle so from your reference

color burst as you shift it to create different colors in that pixel stream.

Here's magenta there's red there's yellow there's green there's cyan et cetera right.

That's how you encode the color in the signal so it's encoded in phase super brilliant to encoded in

phase but kind of hard to extract out because you have to have filters in phase like loops and extract

this information.

So the whole point of it is this is a really nasty analog signal.

The sync is in the signal.

The color is in the signal the luminosity is in the signal horizontal vertical sync all in the signal.

So basically everything is in one single signal line so you can encode this in a signal line and ground

and then you have your video signal.

That's what your component video or excuse me composite video on your TV set the composite the old school

composite when you plug that in.

It's looking for the signal in a ground and that's it.

It's all encoded in her SB extractor.

So during the encoding and decoding it just gets really messy and yucky and then the signal doesn't

look good.

That's why we like red green and blue because it's like red green and blue.

So I want the pixel this pixel to be red green and blue.

Then the next time frame I want this thing to be this red green and blue.

Then typically are RG v monitor has a separate signal for sync so it'll have an H sync and a v sync

separately working out of the mixed together called composite sync.

Right.

Or sometimes even if they want to save signals they'll take the sync signal and actually embedded in

like the green.

So to be sync on green so you see red green and blue and there's only three signals you like where sync

well it's in the green.

So you see red sync on green and blue and sometimes they actually put it in the other channels also

but the majority it's in green.

So anyway the whole point is that's what NTSC is all about.

It's an analog signal invented in the 40s and 50s and that's what all our TV shows have been using or

a variant of and European TV is that use Palen seek and we're very similar.

All right.

Now if you want to know more about this in the book for the course.

Let me go grab that.

The design your own video game console manual here.

My book if you go to Chapter 9 and go to the graphic Section 9 9.

I'd like you to read the graphic Section 9 9 just kind of go through here and it'll show you.

And you know when I wrote this I have all the details here much better than I have off the top of my

head now.

So here's the distribution of NTSC PAL and seek them.

All right.

And then here's how the raster works.

So you know like I said I've done a lot of work with NTSC signals and generating them with hardware

and software.

And this is this is you know a very very good explanation of this at a practical level so you know I

would highly suggest you read what I wrote here.

It took me a while to generate all this for you and for readers.

So try reading this and you really understand what's going on and let's see if there's anything else

here there.

Oh there's that video signal that we just saw with some more details and then getting some more nitty

gritty here what these signals need to be looking like.

And then I talk about you know how to generate them how to generate this stuff in software and hardware

and then talk about it in the abstract so read through that.

That'll kind of give you an idea of you know how to do this stuff.

All right.

Now let's go back over here to our schematic and

this one here.

OK.

So we want you know to basically say where inside of this TV schematic this TV set.

If we had a red green and blue signal and if maybe if we had red green and blue we're gonna need to

sync also where would we put it.

I so I have a game console or a computer that puts out red green blue N Sync and I know this TV can

do it because it's an RG v CRT.

At the end of the day red green and blue the hardware is here to do it.

But where on earth do what do I do.

How do I do this.

OK.

So again this is a big project but I just want to kind of show you my thought process and how I get

into this so the first thing is if you're interested let me go back here and let's see here.

If if we just type in let's go CRT to our G.B. let us do that and then we go back here and then.

Oh well this is interesting.

So what this is showing is in these pictures these are people who have done this and then showing the

different video quality so you can see right here even though he's got the sun on this this image right

here and then you compare this image it's much cleaner.

And then again this image right here and then you got this image right here it's showing these you know

all these different monitors.

So this is a composite video and it's just it's horrible.

Then you've got this RG be model where you can see his eyes.

Everything is just so much clearer.

Here's another picture and RF composite this sexually this actually a good one let's see.

Can we.

Can we open this in a new tab and make it big and of course not.

It opens up the whole thing.

This is this is probably a good good page right here too.

Yes.

So again this is be this is hard for you to see but you're looking at a monitor of a monitor and video

video that you can see here is RF.

So this is the modulated NTSC video RF radio frequency.

There's the modulated video and that's up at some high high frequency and then now the composite signal

has been extracted through D modulation.

So this has been extracted but it's still an NTSC signal.

So they both look you know the same.

They both look bad.

All right.

What's interesting here is this anomaly which I'm not sure it looks like the pillows were there in that

picture in the not here but they're almost identical.

Then we go to s video which is super video.

And the difference between s video and composite video in composite video the Luma signal the brightness

and the color are mashed together in that sync single signal that I showed you.

Right.

But in s video super video Luma and Chroma are separate.

So this is actually a pretty good video standard an old video standard.

And you can see this looks much better.

Again you can't see it that well but if you look at the character here it's blurry everything is not

very clear.

But here it's much clearer.

All right then here's an hour G.B. so forget the Y movie part just this is an RG GV signal.

So this is extremely clear.

And then here's another hour G.B. look how clear this is.

This looks like a computer display right.

So that's why people like our GV very it's you know extremely clear even on if you take an old CRT from

the 70s or 80s and you jump forget about all the NTSC hardware and jump over and plug directly into

the RG B driver and then inject an RG B signal from a game console or computer.

It's crazy how good it looks you just like oh wow I cannot believe how good this looks like you know

here's another example Sonic the Hedgehog.

There is composite look how horrid that looks just a train wreck.

I can't even see Sonic.

All right.

Look at that.

You can actually see everything perfectly just like a computer display like an LCD or modern display.

All right.

Now let's go back here and scoot back here and then go to all and again this is a process you know guys

and gals I don't like editing everything out.

I like you to see how this goes because this stuff doesn't take two minutes it takes 22 hours to do.

Right.

Takes a long time being an engineer in engineering and doing things right we got to find this stuff

out we got to figure it out.

So if we type in CRT to RG B we could even put mod in there but what.

So I want you to kind of do that CRT RG B modify you feel like it.

There's some good examples of people that have done this and you can read about it and so forth and

kind of go through here and watch different people do things now.

The thing you want to be careful of a great majority these people do not know what they're doing.

Some of them sort of know what they're doing but they are hacking things without understanding side

effects and so forth.

So you've got to take things with a grain of salt because a lot of people don't know what they're doing.

And some of them that are good admit they don't know what they're doing.

So they'll say hey I've talked to an electrical engineer and they said do this and this.

And then they go and modify the board and so forth but they don't know exactly what they're doing so

just be careful when you're watching stuff.

And again if you are going to if you're thinking of playing with doing any of this and for fun maybe

you are a retro gamer like me and you want to do this modification please do not mess with a television

set.

If it's plugged in right.

Make sure you learn how to discharge it wear rubber gloves rubber shoes wear goggles glasses if you're

probing around messing around because the TV will absolutely kill you.

So be careful messing around with the CRT TV.

Know what you're doing and just wear protection your goggles your your glasses your gloves you know

rubber Soul Shoes.

Don't mess around with the stuff you see these guys playing on here soldering and probing and trying

things you could really get hurt and it just shocks me the kind of things that people do thinking it

won't happen to me.

All right.

So anyway there are videos on here so you can see other people kind of doing this.

All right.

So that's that now.

So let's go.

And so one of the ways that people have done this is this.

They they take a selfie if you do something like this.

If you say TV with OS the on screen display.

Right.

And we'll do an image

all right.

This is what that means.

So here's our TV and of course I click on the worst possible image.

All right.

Thanks for that.

Here's a TV or a computer monitor is displaying on the screen no windows it looks like right.

Windows 7 or 10.

But here's the on screen display so the TV set or the monitor generates this on a screen display and

then overlays it or mixes it with the video signal.

All right.

Now a lot of these CRTC have onscreen displays right.

They have on screen displays.

You press a button like now I'm looking at a monitor right now as I'm doing this.

But over here is a TV which you can't see.

I can press menu and then the video can be playing and I press menu and it just overlays on top of it.

So that hardware if you recall inside of this schematic let's go here and scroll down to that block

diagram right here

and looking at this white screen is like burning my eyes right now with these allergies you can't I

can't even tell you I can't even talk about it cause then it makes them hurt more.

All right.

So let's go to the block diagram.

So check this out.

There is that video chip.

This is a chip that drives the CRT.

But here's the controller chip and that controller chip.

This is as microcontroller microprocessor microcontroller here that controls all TV set.

This is the brain.

But it also generates this RG v signal right here.

This is the on screen display.

So what a lot of people do is they say well wait a minute here is this controller chip.

This microcontroller that controls old TV set when you turn on the on screen display this red green

and blue is an RG signal and it goes right in here.

So there is an input for red green and blue right there that then this video processor chip will then

take and then amplify and do everything it needs to send to the driver board which is connected to the

yoke which is connected to the CRT.

So rather than us messing around with the driver board and high voltages and all the crazy stuff we

can inject the signal right here.

So right here.

So now here's what these signals mean and here's another thing about schematics.

When you see a thick line with a bunch of thin air lines it means it's a bus.

It just means that this single line represents all of these signals.

They're not mixed together they're just on a bus.

That's all you have to draw for signals.

Ok this red green and blue is the RG That we want and then this bill could be OK.

This is not black.

This is blinking.

So this signal what this does is this blinking signal goes out and it says to turn off the on screen

display.

So the blinking signal turns off the on screen display so that the normal video shows or you turn on

the on screen display and then it goes through.

So we want to control this blinking signal and we want to can inject into this red green and blue.

All right.

That's all we need to do.

All right.

So now the question is.

All right.

Some things come to mind and again I don't want to do this whole project with you because it's very

complicated but so we've got red green and blue.

What format are these red green and blue signals.

Well they're an analog.

They're analog voltages each one of them.

And they range from about zero to one volt.

OK.

And actually zero to like point seven volts is is accurately where they are because there's the way

that this video specification is it's like zero to point seven volts and from zero below like a negative

point three volts is the sync range.

So anyway it's about point seven volts analog.

So we know that.

All right.

Now the RG v coming out of whatever device we have typically will match that but we have to look at

it.

So first you have to understand what these RG v signals are what their format is they're analog what

their voltage RANGES are so that when we inject the RG B signals from our video game console or a computer

or whatever it is our AP computer video game console we put red green and blue in here.

Right.

And then we basically say turn on this.

This blinking signal here so that we turn off the normal video signal.

Right.

And then we inject the signal in here.

We want to make sure that we match what this chip is expecting.

OK.

So that's very important right there right now.

So we've got red.

We've got rain green we've got blue we've got this blinking signal now let's go look at the schematic.

All right.

And also so let's look at these two chips.

So this is I see 2 0 1 and this is I see two thousand one right.

So remember that for a minute and let's go down the schematic let's take a look here.

All right.

So there is the icy to a one hour video chip right in now.

So here is that CRT out.

Those are the signals right there which you're going to the driver.

So now we're all we're looking for.

Where are those signals coming in from our our other guy the red the green and the blue.

And if we look here closely here it is OSD an on screen display in red green and blue and then there's

that blinking signal.

Now check this out.

So here's the blinking signal and it's got a pull down on it.

You know what that does

so that that that keeps it pulled down so it doesn't flow so to turn this blinking signal on.

We're going to assert a high to it now.

I'll tell you right now that the blinking signal is digital.

All right.

So we've got to look here and we got to say well this chip is is this a digital chip.

Is this.

Well obviously it's analog and digital mixed but what power supply does this use.

Right.

So we have to make sure what it is expecting for power supply.

So if you look here.

So check this out right here.

Here's a nine volts right here.

And this is going into this V subsea C so check this out.

This says nine volts right here going into v subsea C I think.

All right.

So we got to we had to figure out what the voltage is that this thing is being power.

So these subsea sees at nine volts I believe.

All right.

And then again you got to look at all these different signals.

Now check this out.

There's a SDL and.

That's an ice squirt Seba so you can.

This actually has ice squirt C bus to control it.

So that's cool we can do things to it.

Now we don't even know much about this chip but we're going to find out in a minute.

I'm going to show you the chip.

But you know you kind of go through here.

We know that we need this red green and blue we know we need this blinking signal then we can see on

red green and blue.

These are capacitive Lee coupled.

All right.

So their capacity coupled signals so whatever signal we inject into here this from this red green and

blue it's going to get capacity coupled.

And check this out there's pull downs on here.

Also capacity be coupled.

So whatever the signal that we send in here is going to basically get the DC components going to get

removed off of it.

All right.

OK.

That's fine.

Now we go look here.

And so here's this whole bus red green and blue and this blinking it's on this line right here this

line right here.

This line right here.

This line right here this line right here.

So red green blue and blinking.

This is how the schematic shows things go to another page.

So red green and blue.

This is basically a signal to another page.

So now let's go find the other page there and there's our speaker right remember that.

So let's go find the other page.

So here's the other page.

And then we go over here.

There's our red green and blue and our blinking signal.

Now at buses and backup just represents a bunch of wires.

I know it's hard for you to follow this so just I'll just kind of go in here with my little hand go

up here and there we go so goes to these pins right here and then there's a couple of resistors here.

So there's a six point eight case six point eight K and another six point eight K and another six point

eight K so all of them just have a six point eight K for the red green and blue.

And now if you look at.

So now let me show you what's happening here.

So you've got six point eight K coming out of each one of these.

Now this thing this chip this I see 2001 is the driver.

This one's driving the RG signals for the on screen display and sending them to that driver chip on

the page above.

Right.

So there's a resistor coming out here right.

And it's six point eight K.

Now let's go back up here.

All right.

And let's look at all those red green and blue inputs right here.

Check it out.

So then there's a two point two K.

Right.

And then there's this two point two K two point two K two point two K and then a three point three K.

All of these are to ground and then from that node goes through a capacitor.

Let's look at that circuit.

Let's look at that circuit.

All right let's go look at that.

So this is what these circuits look like.

Wrong 1.

And so we're you know we're just engineering here.

We're trying to figure out what is going on here.

All right.

So.

So I'm just going to kind of draw this for you.

So here's the red and it comes out and then looks like this so there's the red signal and I'm going

to do the green in green because for once we have colors of things so we'll take advantage of it.

And then here's the blue red green and blue.

OK.

All right.

And then let's go back here.

So let's draw these Zen

and this guy right here.

This is and again you know I'm drawing on this graphics tablet which is way better than drawing on the

mouse was still not easy to do.

I'll tell you that.

So this is this controller chip.

And again we're going to so it is not this icy to a one but this icy two thousand one.

This is the signal the chip that actually generates those signals.

So they go through a six point eight and then on here each one of them red green and blue red green

and blue.

It goes to ground through a two point two and then the the blinking is a three point three.

All right.

So now.

So this is the 2001 I see 2001 chip.

So let's now put those values there.

All right so this one was six point eight K ohms.

This one is six point eight K ohms soup's because we're just trying to figure out what's going on here.

Right.

What's going on.

What's up with the resistors.

All right.

And then each one of these goes through a capacitor.

Right.

And then the capacitor the capacity of the coupled signal then goes into that driver Chip.

OK.

So if we go back here there's this capacitors they're all just point one at 16 volts just means they

can tolerate 16 ball.

So these are just point ones.

Let's get it back right here.

So this is zero point one micro Feride and zero point one micro.

And last one and then you know the whole idea here is we're just we're just trying to make a little

simple models of things.

And then if we have to we'll go to Proteus the simulator and then we can simulate these so these are

all going in to the inputs on the other chip.

All right.

So this one is the controller chip and this one is the driver chip

and it's funny when you've got allergies it's bad.

It's like you're high on drugs.

Everything you're just woozy woozy woozy right now which is what I am.

All right.

And I haven't taken anything to be woozy it just it puts you in a state.

It's terrible.

Anyone who has allergies.

I'm sure you can empathize.

OK so here are our inputs in signal is flowing of what color we're going to signal.

How about this color.

So signal is flowing this way.

In each one of these obviously.

Right.

Same same direction and each one of them signals going that way.

OK.

Now what's interesting here is these right here these resistors are two point two K two point two K

two point two K and then what's our last signal here.

We'll just let's just go ahead and draw it in.

Oh.

Cyan.

This one is this last and I'm going to unfortunately kind of go like this for you guys and I'm going

to kind of just put this right through here like this and there's that and this one again is zero point

one microfiber Feride is their coupling capacitor on there no there's not the blinking signal is not

AC coupled.

Right.

Which I would expect it not to be.

All right.

It's not AC coupled because it's just a digital control signal.

All right.

But this is six point eight K here again and then this one here was three point three K.

OK.

So what what's going on with the resistors.

Well what's going on with resistors is this whatever signal comes out of here whatever signal comes

out of here whatever signal comes out of here or whatever signal comes out of here and this signal is

a digital signal whatever signal comes out of these three analog ports.

This is a voltage divider.

So this is a voltage divider so the voltage divider is just two point two K over six point eight K.

All right.

So two point two K over six point eight K times V N so.

So V out equals this times V in where here's v n coming through here right in V out.

It's going to be the final voltage here.

Right.

So basically if we just look at this right here get our calculators out you can clearly see that's a

third.

Right.

But we just two point two divided by six point eight right.

It's a you know it's point three two but basically a third.

So the whole the whole idea here is is whatever signal we put in here we're going to get a third of

it out.

So if we put out a Volt if this is a say 1 volts here right out here we're going to about Point Three

volts.

So that's what this is doing this is scaling this because whatever voltage This is putting out this

icy tool one it's a little too high for it.

Right.

So these resistors are picked the scale that voltage down then once you have that skilled voltage right

here right then we're gonna get through this capacitor and we're going to remove the DC component out

of it so that what we're going to have through here is a signal that is like this we're here is 0 whoops

we're here is 0 volts here.

All right.

So this basically removes the DC component and then we have this kind of signal coming through here.

Then the driver can use it.

Now over here on the digital signal this is the blinking control.

This is just digital.

And so again he's got a six point eight a three point three.

He's dropping it by about 50 percent.

Right.

Three point three K over six point eight K right.

That's about 50 percent.

So V out equals this times have been so whatever the voltage is here.

You know it was five volts whatever.

Now it's gonna be two and a half volts over here right.

So if this signal over here happened to be a five volt pulse we're just gonna get a 2.5 volt pulse over

here.

All right.

A little bit smaller.

That's all.

That's all that's going on there.

So those three signals are what we have to mess with and inject into.

OK.

Let's hold that there for a second now.

Now the other thing that I got to do when I messed around with this kind of stuff is I need to see you

know these chips and understand them kind of in detail.

That's how I read about what these red green and blue levels are.

And the blinking and all this.

So we need to figure out you know what these chips are.

I mean I can see the pin out of it but I mean I want the datasheet for the chip.

Right.

So let's back out here for a second.

So I see tool one is it's got one times three to five see that might be a part No I'm not sure but I

know it's called I See tool one and again this is this is reading these things depending on who makes

them.

It's kind of like a detective novel.

All right then this one's I see 2001 and it says one times three threes six XY Okay I'm going to tell

you right now there is no way that both of those chips have similar part numbers there red radically

different technologies.

This must be an internal part number for sharper Sony made this thing.

This is sharp.

This is an internal number because they make millions of TV sets right.

Maybe billions of TV sets.

And so they have their own numbers for all of their eye sees and parts but we don't care about those

numbers.

And where is it right here.

All right.

OK so we just need to go look up on a bill of materials.

If there is one.

So the question is in this service manual is there a bill of materials or a parts list.

Let's go see so we go down here here's the actual layout on the boards.

Real nice.

You can see all that cool.

And again this is great to look at.

You know this is the guys who make these TV sets are analog gods.

They know what they're doing.

So you know it would not hurt you to look at all this stuff see the layout.

All right.

And OK here we go.

Parts list on page twenty one there is a parts list and just seeing all the different parts.

Now here's our integrated circuits.

There is our tool one there is that internal number that we just saw right and there is that 2001 and

there's that internal number see and they're so similar right.

I'm like There's no way those are actual numbers.

This is the number.

There it is right there.

So it's a t a 12 68 and is the two that two hundred and one driver chip.

And then it's a Tempe eighty seven hundred CPF 164.

All right take those two numbers.

Now let me blow your brain up a little bit more.

Take those two numbers and then google them.

You start Googling them right.

So this is the process because I do not recognize either of those and no one does.

So I take this right here T.J. twelve six eight and we go into Google.

All right let's see if that comes up.

All right.

And then immediately we got lucky and it came up on datasheet doesn't mean it's the right Chip.

Could be anything right.

But we know it's a driver chip.

So then we look here and we say OK T.J. 12 six eight is kind of coming up without the end part.

Close enough it says I scored see bus control NTSC chip color that.

That's it.

There it is.

And we click it and then here we go datasheet.

So there is the actual data sheet.

All right.

We could click that and I already did this.

But it's going to come in this little viewer here.

And so this this Web site's called all data sheet dot com.

So there it is there is our chip.

Now already did this for you and it's actually sitting right here.

There it is.

So we'll look at that in a second.

So there is that chip right there.

So that's the driver chip.

But now there's the controller chip.

And you know there it is right there.

But let's not cheat.

All right so there's a controller chip.

So now let's go back to our

schematic and our driver chip was this one.

But the controller is this one and it's this TI.

Eighty seven hundred.

This guy.

All right.

I'll tell you I had a hard time trying to find this one.

So I'm going to go back here and I'm gonna just google it.

And when I google it this came up.

And then there's a reference to it here.

Right.

And then if we say here we could say datasheet also all right.

And then this it so there's a reference inside of the and then here is the data sheet which we could

probably go to Data Sheets PD f here and then hopefully it will end up someplace weird.

All right menaces click to download PD F so I think I found it here.

And what is it.

It's a 8 bit microcontroller.

All right.

And then here is it showing the first page here whatever.

So we'll just click download PD F and we got the same thing.

And there it is.

So one hundred and sixty one pages.

No joke you got to read through you got to read through this little bit but you know if you look at

the specs of this thing it's an 8 bit microcontroller 16 k bytes whatever it's how these different versions

of it Ram 1 k by two K by.

So let's go look at the real version right.

So forget about all this stuff we already did this and I just can close these windows and I've already

got it here.

OK so here is the driver.

And then here is the other chip that we just saw which is the controller chip.

So now we know the controller is like a microcontroller controls the on screen display.

That means it's analog though it's a microcontroller that has analog stuff in it.

Sure they will make chips that have analog stuff in it because it goes in a TV set and if you make 10

million one hundred million DVD it behooves you to make a chip just for a TV.

So let's we're not going to read through 160 pages but we're going to look here and just kind of look

through this a little bit and I'm I'm looking for a clock generator reset circuit.

I am looking for is there any kind of video stuff in here remote control signal processor look at that

remote control that's just processing the infrared from the remote control HD converters check it out

on screen display so inside of this chip is an on screen display circuit.

There we go.

So now the a eighty seven hundred.

So on and so forth or two tuner 51 characters and any character is going to be slayed on area of thirty

two columns by eight lines.

So it explains what the graphics capabilities are here.

It shows the onscreen circuit what it looks like and then the output signal generator up there is our

read there is our green there's our blue right.

And then this is a Luma or it's Beetle which is means that blinking control it's showing what this thing

is does and so forth.

So there is that circuit and then we would read through here.

Now we don't need to program it.

We just need to know about its levels.

Right.

So we would go through here and this is all very interesting.

So I mean if you you know if you have time you know kind of pass through it like I am right here.

It's very fascinating and I've read so many of these data sheets probably hundreds of them in my lifetime

maybe more understanding how CRT controllers work and in graphics can chips work.

So you read through here and then right.

And then here might be some information about signal maybe I'm looking for the signal specifications

which might be in the DC or AC electrical characteristics in the bottom of the of sheet but I'm just

kind of scrolling through here to see if I can pick up anything with my eyes here's all the register

sets inside of the chip.

Very complicated very advanced obviously a hundred sixty pages is not a simplistic microcontroller.

And then you ask yourself well how do they program this.

Well they have a tool set.

They write code is probably an assembly language for this thing and then you know this is kind of showing

some of the video signal the you know how is the on screen display.

So all this stuff in here in some more showing you some of these signals it's probably in this area

talking about those levels that we want to talk about.

And yeah so reset except OK.

So this is interesting oscillator so this is kind of showing what these circuits look like in yeah.

So here's what these circuits look like and the question we have these are each one of the iReports

that red green and blue what does it look like.

So here's the electrical characteristics output currents input voltages output voltages all this kind

of stuff.

And then what we're looking for is that red green and blue and might be here and it's going to typically

to be under AC characteristics.

And again I don't want to sit here and figure this all out right now because it's a big job.

But anyway this is this what you do you go through here and you figure all this stuff out.

OK now so we're running out of time but we've now got the data sheets.

We kind of know what we want to do.

The deal is this we want to or I want to we have this situation here we've got that controller chip

we've got that driver chip.

This is how it's connected.

So what I'm thinking I'm going to do is this.

Now you'll see some people do this.

What they'll do is they will connect on to here right there and then or you know anywhere at this node

or they might do it right here.

But the point is they'll kind of connect on like that like that like that and like that and then they'll

connect this thing up to their red green blue and blinking signal.

But the problem is is the blinking signal blinks the normal video but it doesn't blink the on screen

display video.

So you'll see.

So you're mixing your signal with this signal here.

There's this impedance here.

This is kind of a messy way to do this and you're kind of mixing these signals together so a better

way to do this is to actually cut these lines so you actually cut these lines and you know literally

break open the line there break open the line there break open line there break open the line they're

cut the lines open and then you have four signals coming from here.

So we've got those four signals will draw the first four in this purple.

So one two three four then.

Now we bring in our four signals so this is this one was from the on screen display.

This is from the on screen display chip.

This thing all right.

And then we bring in our four signals one two three four.

All right from our our G.B. and then this little blinking signal which is just a control.

So that could just be a switch.

But anyway then the whole point is then we want to take you know one two three four signals out.

Right.

And now what I'm going to do is I'm just going to kind of represent this to go like that and go like

that and then I go like this.

And then the whole idea is we just put a switch here.

We put a switch and we can switch these four or these four then these four signals then we take and

we reconnect right there right there right there in right there.

So basically we electronic we switch either electronically or with a mechanical switch like a big four

pole switch all the signals all the signals boom then on our RG be on our RG b side which is here we

put whatever resistors we need to do the same.

We want to get the same voltage right.

And so we're going to look at this icy tool 2001 what it's outputting voltage wise for red green and

blue etc. so that when we take our RG v signal from our game console or whatever we're going to put

a similar kind of network we can't mess with the six point eight because that's coming from the chip.

Right.

So we have to put whatever our resistor is here so we get the same kind of division.

So we get either 30 percent of the signal or 50 percent of the signal.

All right then the last piece of the puzzle is this is red green blue and this blanking basically turns

on and off this on screen display thing but we still need sync.

That's a problem.

So where do we get the sync from.

All right.

So red green and blue we've got.

But there's no sync.

OK.

So now we go back to our schematic all right.

Go back to our schematic.

Let me bounce out here and let me go up here.

Go back up to the top.

So where does this thing come from remember I told you it's in the composite signal.

So here we are at the block diagram again.

Let me zoom into this now

so we come in and there is that video signal there is that composite video it's got Luma.

It's got Chroma and it's got sync on one signals on one signals all in there.

Right.

We need to get that sink out of there.

So that signal comes in here it comes down here into this driver chip and it says external in and then

it's got this little switch here.

And then there's also TV in and then there's this video out.

This video out signal actually goes here.

And check this out it goes here and then it comes up here into this buffering trap.

What does that mean I'll tell you in a second.

Then here's Luma and in Chromium.

So check this out.

This buffer and trap this.

This is what you know they kind of call filters traps.

So what this circuit does here is as this thing comes up here right.

This extracts out the the Luma this chip this circuit and then the chroma is here and then both are

brought into these two pins.

OK.

The sink is actually in there still the sink is in here.

So this could use the sink.

Now this video out is also going here right here to the S.S. pin.

And then look here there's C.C. sink.

So see this.

So there's a sink here.

So there's some sink stuff going on here.

Right.

So the bottom line is if we could we can just inject into this video line so we could put red green

and blue and connect it to those red green and blue lines then we could take our sync signal.

Right.

But we would have to have composite sync from our red green and blue so we'd have to have horizontal

and vertical composite sync merged.

We could actually just put it into this video signal in this thing.

Would this a circuit would extract it for us.

Right.

But I don't really like that that's that's you know that's not clean.

So what we really need to do is figure out where exactly we can inject horizontal and vertical sync

from R R B output device which is our game console or our computer because it's gonna have red green

and blue and it's going to have either H sinking v sync or composite sync on one line or maybe it's

going to have sync on green.

It's got sync Hungary that's also a different story.

We talk about it but let's assume it's got red green and blue and then it's got horizontal sync vertical

sync or it's got composite sync with horizontal and vertical on the same line.

In that case the question is how can I get that into this chip here.

How can I trick it.

Right.

So then check it out.

We can go into the schematic again the deep schematic the detailed schematic and we zoom in here and

we start to see so there's Y N That's Luma in there's Chroma in there is the TV video signal.

And so if we were we could just take the composite sync.

We could probably put it here and this thing would probably extract the sync for us but check this out.

And after it does that it actually generates the sync out.

So it actually extracts the sync from the video and then sends that sync out.

This chip does all these processes.

But look at this here's H sync right there.

And then there's probably there should be a V sync someplace here and you guys can probably someone's

already probably found it.

There's H sync there's H horizontal out.

Anyway the point is we could find where on this to inject H sync and V sync separately if we had them

we could do that and then switch into here also or we can just take a composite sync and we can inject

it into this kind of video in with our switch also so it's nice.

So there's a lot of different ways but we had to look at the schematic we got to figure it out and it

went but we know how to read these schematics now we know what these things are we know what these resistors

are and we know what these transistors are doing.

There's another MP transistor there's a PSP transistor Transistor.

This look at this right here you know here just this little circuit right here.

If you've taken the class or you're in the middle of the class what is this circuit.

Well look at this we've got some kind of you know this is driving this way whatever.

But look at this construct is here.

Well there's an inductor there's a capacitor there's a resistor an inductor inductor capacitor.

These are filters.

These are filters.

These are so there's filters air filter here.

So this is basically this is a filter block.

That's all that stuff is member this is you know there's an L and there's a C and it's got a certain

response and you add them in series or parallel and you get certain responses there's filter block blocks

right there.

You know again there's a normal diode right there.

There's a probably.

Yeah.

This is another Zina dial three point nine volts.

So any way you go through here and if you have to dig down and understand a schematic you take your

time we try and figure out what it's doing remotely.

And then you add your design elements that you need to and then you know test it so that.

So that's basically it.

So you know I wanted to show you how you would go about you know how do you reverse engineer something

how do you hack something you got to get the you know the servicemen you got to get the data sheets

you got to get the designs you gotta get the schematics then you got to dig down into the data sheets

and the chips and understand what the signal levels are going to start injecting signals and and connecting

things and then understand what the ramifications are.

But then you got Hassan the global What is it you're doing.

We're missing growth and NTSC TV trying to hack it into an TV you need to know something about NTSC

and RG You need to know how CRT works you need to know that it generates a stream of electrons and accelerates

them towards a screen and then when they hit the screen they hit phosphorus and the phosphorus give

off light.

It's a quantum level device you can understand all that stuff.

Not every detail but you know the general picture of what's going on so that you can hack this and do

whatever and all of this is just so that someone can play an old school game console on a CRT and get

a better picture.

All right.

So I hope you guys enjoyed this kind of little example of what I do sometimes for either fun or for

money and this is a you know engineering for you so hopefully you learn that you can read schematics

you guys know how to do them if you've been taking the class we know what all these components and you

know what a lot of this this is very analog you guys know this now you know what filters do you know

capacities do we know what inductor is do you know transistors Do you know what all these things do

and these chips basically are you know these black boxes at this point you don't need to know exactly

what they do but you can understand the signals coming in and out because you understand the constituent

components because we've studied them all right.

So anyway I hope you like this bonus video.

Have a merry Christmas if it's something that you celebrate and I will see you in the next lecture by.
Questions
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1 question in this lecture
Maximo Balestrini
Voltage divider calculation in Lecture 140
I think there's a mistake in the voltage divider calculations. Shouldn't it be: Vo=(2.2 / (2.2 + 6.8) ) Vin instead of Vo = (2.2/6.8) Vin ?
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