Hi check out what I found in the dumpster. Ordinarily I wouldn't take CRTs like this. but I thought: hey I'm into vintage computers so I don't actually have a proper RGB monitor and a lot of like late 80s era computers. they all had like an RGB output and along with the composite video output as well.

But to get the best quality you're really needed, like to use the RGB output. So I thought: try and do a conversion of an old dumpster CRT TV into an RGB monitor and I Just found both of these line side-by-side with a Sony Trinitron it's got a VHS player integrated. Fantastic! I Actually love the form factor of this one this Samsung hITRON monitor here. it's like big and bulky and not terribly taken by that.

and we can almost certainly get a service manual for the Sony I Don't know about the Samsung one. Maybe you know it's not a one hung over and but of course so near famous for their art service manuals so I'm thinking a pair of months if they work now of course. The good thing about this at least this VHS one most likely the Samsung as well. It looks reasonably modern is that it'll have like an on screen display stuff.

which means almost certainly has like an RGB capable chipset on there that's generating a GB to actually send text overlay images to the screen. so that may make the modifications easier to turn into an RGB monitor. So let's try the Sony one. There's a standby: LED Tear up Oh yeah, I Heard the high tension nothing a Hello line works a treat.

Input select. Oh, there we go. That's the of course analog TV has gone the way of the dodo. I might link in my analog TV transmission to a QuickTime over record.

no tape inside. put in the tape program into it. Okay, that looks like it's the Sony's working. a treat Beauty Just try the Samsung No standby? yeah.

I Heard the high-tension startup that's working. A treat. Yeah, of course it's got the color overlay and everything said that one. I Expected these to work.

They're just old. They didn't want them anymore, so they threw him out. They didn't throw them out because they suddenly busted it. red, green, and blue.

It's got like an RGB overlay there that we can actually tap into to do modification directly to convert this into an RGB monitors. Both of these work, but I much prefer the Sony here. It's just. it's smaller.

It's nicer. it's the screen is flatter this. The Samsung is actually quite curved. It's just be like for a big mature, a mono duck to prefer this Sony one.

Very nice. It's kind of like old Macintosh you form-factor have a crack at the Sony shall we? It's got composite in, but it doesn't have any are scart connectors or anything else on the back. And of course a lot of your Sony Trinitron are fanboys will claim this is vastly superior to this Samsung rubbish over here. and they're probably right.

and it's a Kv 14 Vm a 5g for those playing along at home. And if you follow me on Twitter and you should because I tweet like a boss daily and that's where you get all my latest updates and photos of stuff I find in the dumpster room and all that sort of jazz. Anyway, you can get a service manual for this thing but it doesn't seem to be free and when you try to use one of the paid services to get it so you pay your money and it's like file not found great, Put out a call to see if we can actually get the service manual for this thing which will help. We don't necessarily need it, but it's just not and I would like to go through the service menu show you the schematics haven't got it yet, but it does exist and there's tons of variations of this model to by the way.

and I actually like the rather compact nature a compact, but you know, trust me, compared to the Samsung this is just a much sexier CRT Monitor on/off switch RF Antenna input hands up if you remember G-code for her recording programs that was the Ducks guts back in the day. Nice. beautiful, Just a quick visual inspection For dead cockroaches and other nasties. you never know.

They just love the warmth inside these CRTs Well she could do with a good dust out. Yeah, looks in good Nick Otherwise, oh there you go for you yoke fanboys, there's a nice common mode chokes on the mains input there I'm really liking that multi ball construction of course your tape mechanisms all inside. therefore your VCR And we've got these interesting board to board interconnects here which dropped down to a once again a single sided piece of being on that double-sided rubbish cost too much down on the lower level down in there. that's gonna have all of our on-screen stuff that we want to tap into, so most likely we're not gonna be doing any tapping on this board here.

It's the high tension section. no touchy of course. I said the two bits still be charged up. employees Integral implosion protection replace with the same type tube.

Rather good. Nick If it just needs a good dust out, that'll be horrible in the lab. Yeah, you can really see the dust. It's not great.

you really want to give them a good dust out. Yeah, the problem with these integrated units is our well, it's all the high-voltage stuff or CRT drive and things like that. that's all easily accessible, but the one we want the processor board down in there that's not going to be as easy to get to. so maybe like the Samsung which is just a traditional CRT might have been easier to access.

but anyway I like the yeah Sony Now I was going to go and figure out how to get this main board out here so that I can access the processor board down the bottom. but then I Saw this little board got various ribbon cables going to it. one of them goes up to the driver board, then the neck board up here and of course look at the pins RGB there they are fantastic. So that's how our RGB Drive signal and that for all the world looks like a processor board.

So I just disconnected the cables and tada we have a video processor now. This big beast here is it's a Motorola MC 44 double O 2 and we can go to the datasheet for that. and sure enough it's a video processor and the thing we're looking for is RGB and sure enough we have looked three resistors, three diodes here almost certainly RGB and this is the cable there it is B out G out are out. So we need the inputs the RGB inputs for this thing and if we have a look at the border board, interconnect over here.

Sure enough, OSD which is on screen to slate, red, green, blue. So there the input signals. So I thought wow we've really got lucky here, we don't have to take out the main board. all we got to do is tap into the RGB signals on this chip because it's going to have RGB output which is going over here which is going off to the art neck Driver which has all the driver transistors on there.

You can see those there. Sorry for the crudity of the video here. didn't have time to build up the scale and paint it there. Our red, green, blue driver down in there.

So that's what drives the high voltage into the neck. And of course we don't want to tap into that. We just want to tap into the analog input side of this thing, not the output which is going into the Neck Driver. Our pins: 22, 23, 24 There our RGB pins.

but what? What? What? Wow we've come and got. So look the three RGB pins I Just tired via these caps down to ground. That's it. There are no signals going into those pins at all.

So what the heck is going on here? Well if we have a look, here's our RGB inputs down here. I Love these boys who just got labeling to the wazoo. Look at this. It's fantastic.

So Four Five six there. Through these three here, we've just got some test pads. There's nothing doing over there. They go all the way over here all the way over test pad.

They wysiwyg around here and it looks like there we go. some little driver trainees down here or pre drive. the the main ones are up on the main neck board of course. so we've got one two and the third one is down here.

and then these jumpers going over here and then the three signals actually Oh will snake their way up here and basically go directly into the connector here. So it basically bypasses this chip here. although it does, the RGB outputs are over here like this. they do get mixed in with that, but like that's it.

Like we can't just feed RGB into this chip here or we can, but we would have to actually select this as an input anyway. I asked on Twitter and on the YouTube community tab which I'm using more and more by the way and somebody pointed out that this one which I was able to download and in it is the kV 14 Vm5 but it's BR It's the Brazilian model here, but hey, it's not the full service manual, but it's the schematics for it. and here's where we can see the dramatic differences. even though it's the exact model.

this appears different, right? So we know we've got this driver board with this Motorola chip, the 44o, double two or whatever it is and here we go. Here's our video processor over here, but it look it's A it's a CX a eighteen, seven, one five and that's one of the classic Sony jungle ICS I guess they call them I know not exactly sure why the column jungle I sees, but I guess because it's a jungle of parts all around it when you look at the schematic. Anyway, here it buggers off to the neck board. an OS G red, green, Blue Inputs has got the blankie in the pin which allows us to switch between that.

but this is a very different chip to the Motorola one that we've got. And not only that, but it's not it. Look, it shows that it's on the main board so it's definitely like that. Like the pin outs are all entirely different.

It's not like a compatible version from Motorola or whatever. Very different chips. So this one. you can see that the RGB lines they come in here and they come from via these resist dividers here from the Owl system control processor over here.

Interestingly, the icy numbers the same I see 301 I see 301 on here as well, but it's a very different beast. It's absolutely remarkable. Yes, I am aware of the 8-bit guys video on converting monitor into I think it was the Samsung into a large EB Monda and so please don't add it in the comments. and yes, he shows the resistive divider here and he tapped it.

He like did some extra resistors down here and then I can't leave that on there and then tap those off and then switched the blanking pin here. Which we could do exactly the same thing here. but this schematic is not representative of this Australian model thing. It's like they've entirely they've got added a daughter board and the main board is different.

Everything is different. It's nuts. And then somebody else also pointed out this 14 V model. So it's not the V M model and this actually it looks very different.

Pictures: This one's a full service manual. It's got the whole kit and kaboodle of how to do everything. Absolutely fantastic. But the schematic in this is once again.

Oh look, they got the chips and everything I had soft. Fantastic. I Love Sony's service manuals. but yeah it is.

Once again, it's very different. Of so many variations on these models, it's apps, even between countries when it's only the country designator at the end that's different. Remarkable. You would think that Sony would want to like consolidate the bomb and sell it I can understand like power versus SECAM and in tears seeing all that sort of stuff.

but you should be able to build them one model just for that. but no, they just did just change it willy-nilly Anyway, what we're interested in is this Motorola chip and here it is the Chromophore multi standard video processor than AKA Jungle Chip This it's got dust switched RGB inputs with separate saturation control RGB Drive incorporates contrast and brightness controls on a grayscale. all sorts of stuff and I love this simplified a block diagram there God for us. So what's happening on this board here is that here's the red-green-blue outputs.

They go that goes off to the neck board so that's driving the output. and then they've got red green, blue inputs and they do have those AC coupling caps there, but they're connected down to ground so they've not switched at all. And then they got this fast comm input. We'll have a look at that in a minute because that that may be what we're doing.

And here is the Y video inputs that would be coming from, possibly maybe even a second jungle chip on the main board. I Don't know until I really got the thing or I can get access to the actual schematic for this thing. three separate inputs coming from the main board over here and these. please excuse the crew D of the model and when they've got some here.

I Don't know the exact our configurations and these basically mix into these signals here. they basically tap into that and there's a red green blue and they bypass this chips like even though it could use these inputs here, it chooses not to. So I'm not sure whether or not it does. it can't mix them like they want to.

it can't switch iton I don't know what's going on Anyway, they seem to be bypassing on this board, but you know we don't care about having them on at the same time. All we care about is feeding this external input here. And of course there's a where's the I squared C bus down here like this. I Believe we're a go further on the data ship.

We'll see that we can actually switch this input via the I squared, C or Ik and we can at least disable it. But let's look at this fast comm signal, shall we? By the way, here's a very good overview of how this jungle chip integrates with the CIT. Here's our CRT down here. Here's our three transistor driver that's on the neck board that we show Here is the output that we got and then we've got the other lot.

The line output transformer over here got the Tripler which generates the extra high tension of voltage which goes into the that's the no touchy part that goes into the side of the the little on the CRT under there. If you're going to work on these safely, you have to work properly. Just discharge that or I Though often there's a discharge resistor in them, it will actually bleed away after some time. So we've got our RGB inputs over here.

but I'm interested in this first commutator down here and I haven't seen that word used much except in relation to motors. That basically means to switch. Okay, so our first commutator input level is not 0.5 volts minimum, so under that and over over anything over 1 volt. So you could tie it to like five to five volt rail for example.

Fast commutator A very fast active high switch, but it doesn't tell you which thing it switches to, when it it it's high or low anyway. Usually texts on the RGB inputs for overlaying text on picture. We just want to switch right over to the RGB inputs. We don't care that's text or whether or not it's like it's image coming from our vintage PC or whatever.

And this Hardware switch may be enabled or disabled in software, so it looks like maybe you can't switch it in software, but you can enable it now. This does actually go off to a jumper link on the board so we can cut that jump link or remove it and then we can tie that input safely, either high or low. And let's just see what happens cuz the RGB inputs here are effectively are grounded via the the AC cap in there. But if we can get it to like switch over, then we'll know that it works.

This is just the simple, easy test. Rather than having to feed in the RGB inputs and making sure the sync works and everything else, let's just switch that pin over. Just mod that board. I'll take 10 seconds to just jumper that link over and to either high or low I Don't know which ones like me I don't know unless I Put it in there and measure first.

Couldn't be bothered squeaker just to jumper it over and hope you get lucky. So in that case, are we expected to like switch over from SATA the noisy static analog tuner input or whatever it is or the VCR or the line input over to a black screen? an RGB screener and we could tie these RGB lines like we could tie one of these high as well. so you could tie the red Hi. We should just get an all red screen for example.

And what do you know, the typical application circuit has a Motorola 44 140 here. That's exactly what we got on the board, so it's good. It looks like they've just stolen the typical output here and it shows like 75 iron my terminations on the RGB inputs. and if we have a look over here: RGB input amplitude.

there you go. I'm your typical 700 millivolts peak to peak I Believe that's a fairly typical RGB input level. so in theory we should be how to feed RGB inputs directly into there. No resist dividers or anything like should you start a wacom straight in.

And this datasheet is very comprehensive. It's a color, different stages as other blanking and the clamping and the luminance and all sorts of stuff. it's all Actually there's the there's the bypass. Okay, okay so there's our RGB inputs.

fast commutation blanking, fast commentation, logic bypass. Oh yes, right. So it comes in there blanking it. No.

Anyway, it shoves it out there. And because I know some people are going to want to see inside the Samsung one. Well actually one useful part about having a big curved screen in this you can just rotate it. It's a builded rotational thing anyway.

See, this one is much much simpler. to get at the main board down in there you can see it looks like we've got our processor down there and that's our jungle. II video processor chip up there so that one would be much easier to tap into. But as I said I don't know.

this one's bigger. It's in right. So what I'm going to do is actually cut this jumper link here which comes from pin 21 which was that commute eight pin and there's a resistor pull down there so there's the jumper going over there. so if I cut that it'll be pulled down to ground so it's worth.

Don't have. Never forget the soldiering iron out I Just cut that and see if I'm put the board back. see if our signal will change it. see if we get a blank screen, we shouldn't get anything.

we shouldn't get our line said oh no okay oh hang on no it's silly me because that bypasses that. Are you believe that actually bypasses that video processor? So I gonna have to tie one of the RGB lines actually because otherwise it's just gonna be black and that's what we're getting. No hang on. What we need to test is the input select.

ah the analog input video. So and obviously it's not ground don't Okay so what I've done now is just jump at it over to five volts of the link is still gone. So I'm not driving it with anything else. Let's give that a bell now.

Of course Murphy could ensure that that is actually our software disabled as we saw in the datasheet. Aha our snow. We got it. Our snow is gone.

It switched it over. Beautiful. So the height that pin being high switches it to the RGB input and it hasn't been disabled in software. We know where.

That chicken dinner? Okay, so just whacking a little resistive divider there from 5 volts directly on the pin and on to the red pin and see if we get a red screen that's some intensity level my voltage starts up. You should see a line again. Oh no no no red, that's disappointed. What? What? Wha? No trap for young players.

Here's the RGB inputs here and they've got all. I did what? I bypass that I had a resistor divider here and I've come a guts I because that's being overridden and I used like a 10k in a 1k so it says output impedance less than 1 K so it's got to be a seeker board. It's got internal voltage references so yeah, actually doesn't surprise me to stay blank. Oh I need to drive it with either a lower impedance source or with the actual signal and we know Winner Chicken dinner.

if I feed in a just a 1 Kilohertz sine wave 0.7 volts peak-to-peak and it's of course, unsynchronized 2 seeing the sink rate. so that's why it's moving like that and I can fiddle with that. There's two kilo. it's three, Four five.

Hey I Love that. That's very nice. I Reckon I can get that to stop a hundred point six, three Hertz Beautiful. Anyway, that's just fed into the Virant AC coupling cap.

Just a hundred. N So that proves that it has actually switched over to the RGB input on that chip. Absolutely fantastic. but of course it's still got the still got the display on there now.

of course, this synchronization shouldn't be an issue if we feed in both the RCA and the RGB signal, because it should still synchronize from the the composite video input. So that's that's the theory anyway. and hopefully that will go away if we actually plug in a video signal. And yep, it does Alright, let's test out an RGB sauce with this I've got then Ibm-pc Jr.

I'll link in the video for this if you haven't seen it. and I did an excellent repair video if I do say so myself. It was a good adventure on the keyboard as well, but anyway, this actually has a an RGB output, but not a traditional analog RGB app. It's actually got a CGA or color graphics adapter output and that's actually a digital RGB It has separate red, green, and blue signals, but they're actually digital instead of analog so you can only get seven colors with those.

But it's also got a digital intensity pin as well. and when you combine that with the three red, green, and blue, you can get up to 16 colors. So unfortunately, that's a digital signal. but we're going to measure the signal level of that.

but I've also installed a little. What a little switch here that we can switch between the RGB and the composite input. So I've got the composite output from the IBM PC Jr.. So let's switch it on.

Tada. There it is. Oh, it's glorious. Color Fantastic.

Haven't got any. it's only 128 K That's not a bad image, but the good thing about the switch is that we'll be able to between composite and RGB because we have to build a circuit first. Anyway, let's measure the RGB output. So the IBM PC Jr.

uses an annoying custom pin header connector. but I do have the cable that converts that to the standard CGA D9 connector or something. Anyway, one of the RGB signals there. Let's actually turn that off there.

You can see the combination of our one set, the two volts per division, one set to one. So it's basically what a three and a half volt digital signal. So we're gonna have to knock that signal level down to under a volt before we can now feed it directly into our chip there. But we can do that with a simple resistive divider since I've got 220 ohms and 47 hours, she'll be right, but haven't calculated it, but those should be close.

I've got these are AC coupling caps. These are just hanging off in that free air and these will all be all tied together. These will go to ground and these three caps stumps sold of that on the back there and that'll be just. you know it's an OK solution.

I could do better, but yeah, it'll do all right. That should do it quite nicely. I've got even got do them color-coded Okay, that's hooked up to the CGA connector. You'll notice that I haven't bothered with the intensity pin.

There's just no point for the purposes of today's experiments there anything else other than CGA like a real RGB Monda Then like I wouldn't be using this board. This is just a hack to get this working. Alright, let's give it a ball. I Think that's the composite and that's the RGB.

Doesn't like that at all. damn well. Hello! This is interesting. We have blue and sure enough yet we only get all the blue information on the pit screed.

What the okay, that's actually the green line. The red line looks the same as the blue. I Think there's actually something wrong with the the Jr.. because I'm getting nothing on any of the outputs.

Now we're - the red, but we're getting there. It's a bad connection of the custom connector, the pin header connector on the IBM PC So yet that explains it shielding on that Wow They went to town anyway. Watch what happens if I remove the composite. This is the RGB one.

Of course, if I remove the composite. Bingo. It loses sync because that's where it's getting the sync signal. From now.

we know we're not chicken dinner. There we go, that is composite and hopefully you can see once again that shimmer. the black is not black. To switch it over to the RGB and AH like as the Ace of Spades are really like that.

There's quite a significant difference here. Let me pair it up. Get that beautiful Ibi look at that. you know that thing of beauty is joy forever.

That's the composite and that's the RGB. Wow, that makes a heck of a difference. Huge difference in that Once again, I'll show you that rebooted that's composite and that's RGB Wow Big big difference. So there you go: I Hope you found that interesting.

That's how to convert a dumpster CRT like this into an RGB monitor and this Sony one. We actually got lucky we didn't have to disconnect any of the EHT stuff or anything like that. They just had that board in there. and of course yes, I can add a switch to the back of it.

I can add some B and C's or some RCA's on the back or a D connector or something like that. I'm not going to do that in this video I just want to show you that it's actually possible to do that. Yeah, anyway. I like this little Sony Trinitron It's neat.

Maybe it doesn't have the resolution. if the I don't know, haven't looked at the specs of this. how many lines is A got all that sort of jazz? Anyway, it does make a heck of a difference between RGB and Composite. It's absolutely terrific, and it's not that hard to mod one of these monitors.

Short, you've got to use the composite for the sync there, but hey, that's okay. Of course you can use the external sync if you've got that and all sorts of stuff. and we could look at feeding in the external sync and stuff like that. But now I've got a switch that I can switch between composite and.

RGB Brilliant! I Like it and nice little form factor. The Sony Trinitron there. Yeah, it's a little bit out on the alignment and stuff like that, so you'd have to get to the service menu or however you do it and actually adjust the horizontal and vertical shift and stuff on that I Hope you enjoyed that. We had a few little issues, but yep, solved.

So let me know what you think down below and as always, give it a thumbs up if you liked it. Catch you next time!.