Hi! Well, that didn't last very long, did it? If you remember the previous video where I attempted to repair the LCD on this PM 303 face power analyzer here. Yeah, wah wah wah I was able to repair it at the time, but it has returned as I kind of suspected in the video I Didn't know how long the repair would last and sure enough at lasted a couple of weeks or something or a month and then it's like it's dead again. Unfortunately, there's no other way to really fix these hotbar attachable flat flexes inside this. you have to watch the previous video for all the details on that.

Oh, they're often called tape automated bonding or tab connections and they're famously failed in like the fluke scope meters and things like that. and sure enough in this particular module here. So really, after its failed that second time after we are trying to reheat the conductive tape connections on there and it still doesn't work, there's not much you can do except get a replacement, so that's what I did I went I got this one from DT key actually what was that? $40 something like that? It's actually a new it's not a one Hungary and it's actually a New Haven display one and it uses the exact same chipset as the previous one and it's available in like different types. I Wanted like a you know, a nice white one or something like that but unfortunately nobody stock that at all.

so I had to get the same I think I got the same yellow one they had like a blue one didn't want Weinke blue. So I've gone with the same one. so let's rip this thing apart again and see if we cannot work this replacement in here. I'm going to have to put the header connector on it's think it's on the same side I Hope it is because I've seen some of these replacement modules you can't actually buy them on eBay and they I've seen ones with the connector on the other side so they kind of ruin your day anyway.

does have a backlight so we'll have to dodge that one, but that's no worries. You can just solder the wires on if you really need to. You don't need a connection. this is what it looks like now so that's how I will do an A/b comparison.

Oh I think this one is the one with the connector on this side because the numbers here they're the right way up over here. I was going by the anode and the cathode over here if you flip that around or the right in is the correct orientation. and if you have a look at the datasheet, it does show it in this orientation. so that means that the connector is on the opposite side.

but it's not going to matter because I it's a ribbon cable B It goes via this little plugging car which joins the top board wedges between the top board and the bottom board. down. here, it's a weird cube construction and we can just take the cable over to the other side. This one.

here. all the text is upside down, so that's interesting. Have they installed it upside down and flipped it in software because it's just a graphic LCD Module: It's a 240 by 64 graphic LCD But hmm, there's a serial border for those playing along at home. Old-school EEPROM And upside down all the electron that's going to fall out.

that's a Hitoshi H 800 Hitachi fanboys. Still a couple of them around. They go wild. This designs a bloody mess.

Let me tell ya, it's terrible. Anyway, let's get this out of here and I will leave it attached, Won't we? There we go. There's our module. and there the two boards is the original.

Here's the new Newhaven one. Of course, they don't use exactly the same chips, but they do use the same chipset which is the most important thing, which is the protocol that the software talks to the theme with. and that's the are a 69 63 like a chipset core is. Although you can get that core in from many manufacturers, these are our Toshiba chips up there and these are in something I Have no idea.

you can see that they are very similar, but you know there's differences. As you'd expect, like this one uses a cutout in the PCB Here for the crystal up here, this one uses a more modern surface mount one. We've got some extra stuff around here. Looks like a extra power supply maybe as that looks like some local regulation that's a switching converter.

Why else would you have the inductor down in there? Basically, it's exactly the same and it looks like pin 1 is in the same position because your note the red up here and matching pin 1 over here so it looks like they might have actually installed this upside down. I Couldn't actually get a datasheet for this exact one. I Guess this number? you google it and you just get tons of generic compatible ones and you can actually potentially buy cheaper than this. So New Haven one I think was fifty fifty five US dollars which is not particularly cheap, but this is a quite expensive uh, power analyzer.

and I want my display to work, work properly, and work reliably and hopefully it'll be a nicer, clearer display as well because the last one was pretty dull and wimpy. So yeah, hopefully it'll be a nice upgrade. can potentially get it cheaper. There was one seller on eBay but they wanted like a hundred and twenty US dollars postage, which is, yeah, not untypical for Australia even for such a small thing.

Yeah, they just couldn't be bothered shipping it for a reasonable cost. you know, don't necessarily blame him. Anyway, this is the cheapest one I could find was actually on digi-key believe it or not even Aliexpress in other places like that. Nah, you know we're talking like a hundred bucks or something.

This is quite a common module the the 2406 for which as I said is 240 by 64 graphic LCD and any product that uses this particular one that uses the hopper attachment, the tab, the taper order made a bonding or taking apart again and have a squeeze. might have another play around with it and see if I can get it going just for kicks. But anyway, let's install this one. might suck up the connector.

otherwise I've got a fine I could I'm sure I've got one here like a suitable cable in the lab somewhere, but I'd have to find it I Think it's easier just to suck the old one out and and just result it straight into here Me: I could even potentially like cut off the ribbon and re terminate the ribbon if actually I should have a connector, but the lab still a mess. it still looks like that. so in there somewhere is the stuff I require so might just be easier than solder D solder I Just said unsold. Er, what the I swear they've budged a fan into this thing.

There's a little pissant fan on the bottom of that and look, they're just like hots knotted down. They've just budged some wires directly across the main fielder caps there. I Reckon that's a design afterthought. and as we showed in the previous video, there's the culprit right there.

This is a hot bar or tab tape automated bonding process. It uses a conductive adhesive down in here to actually connect that directly onto the PCB And yeah, these things are just notoriously bad and you can try and heat them up and like press down at the same time so sort of simulate that hot bar thing like pressing down and let it cool down in the Fluke repair video. I used in a pencil eraser didn't I But if it doesn't take, then you're just better off scrapping it and the new display doesn't actually have that I won't take it apart if you look down in there. that's just the backlight.

and if you look down the other end, it's just the other end of the backlight like that. So they're obviously using much more connect and many more connections. Much more, Many more connections on the zebra strips along here whereas the original one today. There's a lot of room even though the zebra strips go all the way with LBJ right up here.

So obviously the new LCD has got different routing physical routing on it and it allows them to utilize the space for those connections up there without having do they have the ones on the end. And if yes, they could have just had another zebra strip on the end and been done with it. But yeah, they decided not to. So they come a gutter that that technology is Just dodgy.

It's important to hold these boards upside down when you suck them off because gravity is a mongrel. and now if the PCB designer didn't make those holes as tight as a nun's nasty then we should be able to wiggle this loose. There will be a little bit of snap, crackle and pop there. You might want to get in there and jiggle the individual pins one by one with a screwdriver.

Just use your finger. We can wiggle, wiggle, wiggle. Yeah, look at that. Beautiful.

no pads lifted, thank you very much. I'm a professional all right. soldered that onto the new display soldered on the lead connector. but three chests and it's good to go to put it back together.

That lead cable just reached I had to sort of like even bend the connector a bit. I'm gonna power it on I Haven't put the case back on yet, so let's give it a ball. so it's it is actually in upside down as per the previous one. So let's give it a try.

And nope, it doesn't like that. Bummer. Want Want want want and get it. Got it out of there.

Disconnect the lead and sure enough, it's like full contrast on everything. so it's beautifully dark. I Really like it. Fantastic compared to the other one and it's supposed to be the same chipset.

It says some sort of like a really marginal timing thing. how to be Just my luck. Murphy every time. No.

hold on to your hat. All right, Don't know if you can see that I Think you can just but you can see the text on there. Beautiful. It's actually talking so Houston.

We just have a contrast problem and that's excellent because we can fix a contrast problem. Is there a pot inside so this thing are not working off the butt is a good thing. It means that we've got actually got something to do. It would have been boring video if it just worked off the bat.

Now to adjust the contrast, that's actually the Vo pin pin for on the connector here. Interestingly, they do have like a pot, an unpopulated potentiometer, a little surface mount job' down there. so I'm not sure what the deal is I Looked at the data sheet for this thing that doesn't really have any info on that to have a look at what pin Four is doing over here in terms of the contrast and if we've got a pot inside this thing, so let's whack it back open, have a look. So here's our driver board.

so this has just got a whole bunch of discrete seven four series logic. I Don't see any pots on there but I do see looks like a trimmer pot. They're all the a space for a trimmer pot. It's got two pins tied together which is very common for a trimmer pot.

so I'm not sure if that has anything to do with it because the pins all the way over here and this is all the way over here. It doesn't kind of add up. I Don't see anything on the main board either. There's nothing hidden away in there.

no sneaky little bugger, nothing else. You know you'd expect it to be close to the to the board over there really see anything, so it looks like the other one might have just been hardwired for the contrast, hence why this one is so out of whack. They specifically hardwired that for the previous one. Whether or not it's like two resistors, you know it.

could it be those two down there setting it or you know, who knows. All right, if we actually fly the money on pin 1, 2, 3, 4 There snakes around there, goes over, drops down, and bingo goes all the way with LBJ right around here, sneaking right down to. you guessed it, this area that we saw before. There's no resistor populated down in there, but it's near the pot here.

So uh-huh. And of course, the only reason that you would have a trimmer pot on a board like this is for some sort of contrast adjust. so maybe we can populate a pot in there and give it a tweak. And the datasheet says that the Vo pin is nominally up minus 7.5 volts and pin 9 on the connector is the negative voltage generator of -10 So I'm gonna go pin 2, which is ground, that's a little bit.

Pin 4. Yeah, yeah, there you go - 11 volts. Yep, that's not terrific. Where's pin 9 9? Well, don't shot the pin.

Oh hello. No, like we just saw it come good - 10 point. - Yeah, All right. so we need to adjust that.

Maybe let's try the soldering in a trimmer pot. Maybe she's gonna find one in the lab now. But of course the issue with doing that is the Visa in this case is actually coming from the mainboard over here. So we sort of have to like either disconnect it from over here or change it over here.

There's a couple of ways you can do it. You can of course do the contrast on the LCD board itself using its own supplied voltage that's no problem and then disconnect the wire. you could ever snip it or disconnected on the board over here, or do whatever. Or you could supply the voltage from over here.

But anyway, I might actually go back to that driver board and and just have a look where that pins coming from. It's actually hard to see the traces here because they're on the top side pin 1, 2, 3, 4 and if we trace pin 4 there, it actually snakes just along the top there. you can barely see it, but it goes over to this zero ohm jumper link there. So follow the money on the zero ohm link, it goes to that cap.

There goes the negative of that cap. The good news with that is that if we generate the V 0, generate the contrast on the board, then we can just disconnect that jumper there. Excellent. So just disconnect that jumper just so that in case this is a trace on there that I can't see is overriding that.

And maybe if you get lucky, the LCD might actually bias it to the correct value itself, but then again, it may not. The datasheet has no information on that whatsoever, so if you can't are reliably things that you're actually doing because it's a multi-layer board or whatever you can't see, the trace is going off. I Haven't like just hacking around. Little things like this that you can always put back is often a quick and easy way to do it.

So anyway, I've disconnected that. Let's see if that. Yeah, there you go. So it was overriding that.

It was making a difference. So now we've got nothing. If I measure that V-0 pin, we'll find that there's probably nothing like what we need on there. Yeah, two point, three volts.

No, we need like -, well, according to the datasheet, like a nominal - seven point five or thereabout. So we can potentially do that on the LCD board itself, which I'd prefer I'd prefer to modify the LCD than modify that the driver board in there I Think me six, one half dozen than the other. Okay, hey, let's just have a squiz around here. I've determined that this is the ground.

Of course, the positive is going to ground because these are negative voltages over here. so it's fine so that those tan alums aren't in Reverse So don't worry about that. And this one here is our negative at 10.2 So that's our generator. You see that goes down there, goes through that resistor over to this transistor over here.

this pin here to point Nine. Well, that goes through that unpopulated resistor and that is the trace that buggers off to our V-0 pin - of LCD drive. Basically, which then all go somewhere else in the bias of the chips and everything else. but we're going to feed it in at this point or at the connector over there.

These two shorted terminals of our trimmer pot are actually connected to the So this side of the resistor here. So we've got our Minus 10. We should be able to generate our minus 7 by doing some funny business around here. And for those curious, that looks like an LM three to four down in there.

So to generate the various bias levels for the LCD, maybe if we populate that and the trimmer that might do it, we might actually leave out the one going off to the pin because it looks like this is where it's doing the business. That's just a fur fee, but like if you wanted to control it externally from the board I get. But then how's it getting over that's not populated. How is it getting from pin four of the connector currently where we saw all the dark contrast there, so maybe there is another trace buggering off somewhere from pin four? but I didn't see it.

Okay, that might look a bit ugly, but I had ready access to through-hole once, just worked in a 50k pot in there without doing the other resistors, and I've gone to the extreme ends of both ranges. It makes no difference. So I'm going to whack that other one over there in series. I'll just work in a 1k.

Yeah, nice round value actually. I sold it in a 1.2 K because you don't want to like blow your wad of 1k resistors if you got like a like a no 603 resistor kidoh 805 resistor Kido 402 resistor kits. As you should have in any good lab, you might have like ten or a hundred of each. you don't want to piss away or you're like nice around 1k.

So if you've got a value like this that doesn't matter 1k, 1k, - doesn't matter. take it from the 1k - and what we've got now is the - 10 volts that we had there that's now being fed through via the resistor we sold it in - There is another resistor which is in series with this trimmer pot which then could bugger off to the chipset to do the contrast. So that's the plan. Hello Hey Winner Winner chicken dinner.

There you go. Look at that Beautiful! Now the contrast isn't great because of course our trimmer pot could be anywhere. and once again, we haven't got the backlight. it's just flapping around in the breeze.

so let me see if we can make a difference. Well, that's interesting. I went to the extreme ends of the trim pot both ends and it did nothing. so that's a consistent contrast.

So anyway, we're we're getting somewhere. So maybe the 50k isn't enough my baby. I shouldn't have put the 1k in series. Maybe I should have put like a hundred K in series.

could be swapping it. Whoops. Okay, what? I did instead of the fix resistor is I sold it in a 5k resistor 5k trimmer on that resistor that was in series with this one. This one still does nothing but Tada winner winner chicken dinner.

Look at that. that's beautiful. And yes, the 5k does adjust the contrast nicely whereas the other trimmer one which had the thing on here, it doesn't adjust anything at all. So I'm a whip that off and I physically remove that trimmer and what do you know? So that trimmer was a furphy.

Obviously it has a purpose, but maybe I'd like the external input and that transistor there I don't know the configuration. haven't bothered to trace it out, but look at that, that's beautiful and that's with no backlight still flapping around in the breeze. The contrast on that is just fantastic. Was much better than the old one was.

That's for sure worth the upgrade. Just right there in the contrast. I Think we need a backlight, do we? Hmm. And by the way, yes, the orientation is exactly the same as the other one, so you'll notice like the text is obviously up the right way now, but the text on this side is like that.

so I believe that's the proper orientation. So I think the software is actually flipping that for the purposes of cable management or doing whatever inside there, and that there's nothing wrong with that at all. That's fine now. Of course you can either leave that trimmer in there ordinarily like if you wanted to adjust it because that's it's.

just holding on by two pads there. It's a bit how you're doing you'd normally like even do it nicer. Like, maybe mount it off on the side here, glue it down, run some little mod wires over there, and you know, do it nice and professional like that, Or you could just coat the whole thing in hot snot and that would allow you to screw it without putting any pressure on the solder pads down there, which are tiny. They're only little.

oh six oh five. It's going to be no stress on this thing whatsoever once it's in there. So I tempted just to leave. it can put some hot snot on there just to stop it flapping around in the breeze, but it's not going to flap around in the breeze.

Of course, if this thing was on like ammo, all trolley, test trolley or something like that, you're willing around all the time. Sure, you would sort of glue that down to stop it and vibrating and stuff like that. but just for the lab use I don't know. Maybe I'll just put a bit of hot snot on it.

So for those curious about the adjustment, range goes all the way down. depends on the angle, the angle on this sorry about the screen, the reflections off the overhead lights, all that angles pretty good. Fairly happy with that and that is an after comparison. So I'll try and put up the before and after shots there and it the the film on the front of this.

actually it kills the contrast a little bit. And yes, I do have the backlight on here you go, but wait, hold on to your hat. All of this may have been for Zip. thank you very much to Keane Maysles you probably seen on the blog before Anyway, he pointed out um yes I Do upload this video early to patrons and supporters he notice I've had to come back and reshoot because he noticed that there's a driver transistor here inductor what they're doing.

This is very likely a software controlled contrast adjustment. Generating the voltage is not a fixed thing and all. That's really obvious, but I didn't think this thing had software contrast control. It's not in the firmware anywhere, but if you have RTFM if you read the freaking manual, you'll see that it there is actually after your paradigm.

You can actually press the arrow keys to adjust the contrast. So I'm gonna whack that back in and try that and and remove my trim pot and hopefully it'll have enough range. It may or may not, it's not guaranteed. All right.

let's pair it up: I've put that link back I've removed my resistor. We got our dark screen, but I'm supposed to be able to without touching any other keys. It's supposed to be able to press and hold this key. Oh I can see it.

Maybe I can stay that now. it may not have, may not have the range. Yeah, yeah, it's going darker. Yeah, it doesn't have the range.

That wasn't a solution, so that wasn't a lost cause going through all that. There you go. It just doesn't have the range. Well, so the designers just didn't cater for the fact that there would be other unfortunately just putting the pot back and leaving that link in place.

I Thought I might be able to be clever and actually change the range of that, but ya know, maybe I can get in there and trim it a bit, but it's annoying. So what I want to try and do is actually get electronic control. and I've only got very partial electronic control with the original wire configuration in there. and if I put the trimmer in there, it doesn't really help but watch this.

if I put the trimmer across pins 1 & 4 which is the V 0. So if I load down the V 0, watch this. Get the tongue at the right angle. You know that I can adjust the contrast electronically.

Fantastic. And of course, you don't really want a trimmer pot in there that we've got electronic control now. So if we have a look at the resistance value for point 3k, All right, no worry said, that seems to be a reasonable value. so just whack in a 4.7 K either directly across the pins in there.

but then I could short out to the front panel. Maybe I could do it in there cuz the trace comes all the way here. So between there and ground and that should do it. and then we'll have full electronic control beauty.

So there you go, got a resistor from that point around to the ground of the cap over there. so let's see if that does the business. Tada Fantastic is, of course we didn't have to be 4.3 but 4.3 happens to be exactly in a twenty four value that I had in my kit. A 3k nine might have worked, but it looks like that range is fan-freakin'-tastic Look at that.

Beautiful. There you have it. We now have a perfect replacement fully installed with electronic contrast control. Fantastic.

But it didn't We, We are defied for that. It didn't just happen like off the Shout is put in a module because there's variations in the in this case, the contrast voltage range in the actual product. So yeah, that was actually, uh, hoping for something interesting like that. At least it would have been disappointing if it just worked right? So there you go I Hope you enjoyed that little light repair redux there that we had to go back and fix our repair.

You know, like a month later it was gone skiing. A lot of people in the comments said yeah, it's not gonna last and like apparently, poet people don't even bother to fix these things, they just simply buy the replacement module. It's not worth the grief, so these things are just horrible. These are hot bar you know, tight tab or tape, automated bonding connections.

just a pain in the butt so the new one avoids that of course. as I said by having the extra contacts on the unused areas of the zebra strips here and you can see you can see the contacts many more so the new one would have many more contacts along there and along there as well. which allows to do away with that. And these things fail in all sorts of things.

I think they use them like in LCD TVs and all sorts of stuff. The technology is probably better these days, but this is from like our two thousand of course are. There's lots of products people are talking about the same fires in Game Boys I've seen it in Flook it's very famous in Flook scope meters. Back in the day I've done a video fixing that as well and ultimately it's going to be a band-aid fix hit on there.

Some people said they've never been able to repair these things and that's not surprising. So I Don't think there's any magic bullet you can actually get in there. Maybe scrape away everything if you're absolutely desperate. and it was some weird custom module or something.

you can get in there and scrape away the contacts and actually wire them little mod wires over to each one, down to the contacts, down to the pads down in there. but geez, yeah, you have to be pretty desperate. So anyway, if you liked the video, please give it a big thumbs up. and as always, discuss in the comments and over on the EUV blog forum.

Catch you next time.