Your best option is probably to heat the zebra strips up with hot water or something like that. The rubber material needs some heat to wake up the elastomer and get it to go back to the shape it was molded in.
Oh interesting! I didn't realize that. That's the perfect thing to experiement with the extra set from the other LCD. Someone also suggested the opposite: freezing them to make them harder and sanding them down. I can see trying both approaches.
@@NoelsRetroLab Sanding them down is going to be really difficult because the surface needs to be very flat that there's no good way to fixture them to ensure flatness. Boiling them in water for twenty or thirty minutes with just a dab of baby shampoo or similar salt-free detergent is probably the first thing I'd try. Then wash them with distilled water and let them dry out thoroughly before reassembling.
@@NoelsRetroLab I'd also wait for a while before trying to do anything with the zebra strips. I've had those come good after just sitting for a while (around a week or so). I'm not sure if it's the viscoelasticity of the material at play or evaporation of the cleaning compounds I've used or what. Anyway, it just costs a bit of time to see.
@@NoelsRetroLab I could really see this working. I know for example that "rubber" suction cups that hold thins in an aquarium get really stiff and hard after some years - but boiling them in water restores the elasticity and they magically work again.
I appreciate the thoughtful and straightforward way you approached the LCD’s power problem. It’s inspiring to watch someone carefully work through a problem.
Thank you for this video! I had exactly same issue with my ppc512 bought 20 years ago! It was so worth to keep it all this time to find this video! Screen does work now! Thank you!
Excellent Video, I just dug my Amstrad PPC512 out of storage and fired it up. Still works perfectly on the original power supply. Only used it for about a year in the field, but was never willing to toss it, even after many many moves, thought it looked cool.
@@greenaum Guess you could but I used my Amstrad strictly in the field for downloading data from exploration equipment and putting it on floppy disk. Then in the office transfering the data from floppy to a faster computer with a nice size screen.
Adhesive backed velcro might work too with a bit in the corner at the top or both top corners if required. It probably isn't going to be opened on a regular basis and is easily "undone" if need be.
A more generic name for "Zebra strip" is elastomeric connector. If you can find one that is the right thickness you can probably just cut it to length. The LCD is absolutely terrible though. It would be nice to replace it with a more modern LCD, but I am not sure the interface is standard. Probably not. Excellent video as usual. Happy next year Noel!
Right. I had seen that but thanks for confirming that. I agree that the LCD is horrible, and the final straw is that the MDA mode has horrible CGA emulation so... off to get a new LCD!
Noel, As I mentioned on the first PPC 512 video I used to fit backlights to these PPC screens (& HDDs in the 2nd floppy Bay). To get the screen perfect you need to manipulate it very, very gently when it is half assembled. So, loosen/undo all the tabs on the back of the screen except a couple top & bottom then with the power on and screen connected, very very gently slide the screen left and right, up and down until you see a perfect picture. Your movements will be tiny (and there was definitely a knack to it) but by moving it you can align all those connections properly. Then carefully re-twist all the other tabs checking all the time the alignment is correct. There is no way to do it without the screen on and working! Happy new year, RR
I would fill up that broken handle with epoxy around the screw posts, There‘s a lot of unnecessary space that was left only to make the part cheaper and it would make it really sturdy if these posts had support all around them.
Suggestion for the broken door hinge ... A hobby store should have small hollow plastic spacers / tubes. One of the right diameter and thickness could be cut to the needed length, then in half (or as required) to complete the hinge. When gluing the half in place, use just a little superglue and keep the hinge moving slightly while the superglue initially sets to avoid any seepage from the joint accidentally gluing to the axle (I speak from negative experience with plastic models 😉). This will not fix the clip part ... but I saw an excellent suggestion about Velcro for that.
Noel for the ports panel it might be cool to mount small magnets on the inside of the panel to hold it closed so it’s not “flopping in the wind” as Dave from EEV Blog might say. I think I saw Adrian Black do this for one of his builds but don’t quote me on that... might have been rare earth magnets he used too.. Happy New Year
Great video as always! If you want to go the extra mile to fix that hinge, Shelby from TT has a pretty good method of reconstructing plastic with superglue and baking soda, if I recall correctly he used it for an hinge as well.
Thanks Noel for another great video, and a great year. You guys have helped us through a difficult year, you deserve the subscription growth. 10k plus. Congrats.
Nice job! The Amstrad without its LCD display isn't really the way we remember. :) 4:00 re: the power jack, I was just working on a B&W TV and also found the solder joint cracked on the DC power barrel jack. Perhaps using the electrical connections as a mechanical fastener for a power jack is unreliable after much use. I decided to additionally use some plastic epoxy to attach a new jack to the PCB.
Thanks! It wasn't perfect, but it's kind of working. Now I have my usual "problem" of not wanting to stop once I get going with a particular machine, so I'm going to upgrade it and then try to replace the LCD altogether with something much better. Should be quite fun!
I am curious to see how you get on with that "zebra strip". I have never been able to improve issues when those things are involved but I never replaced them. THANK YOU for your videos, I am always happy to watch them! Happy new year too Noel!
I'm already looking into LCD replacements, but I might go back and try a few things on the zebra strips just for completeness and experimenting. Thank you and happy new year to you too!
When I saw those zebra strips I thought, "oh no". I haven't had a lot of luck getting those things to simultaneously contact the LCD glass conductors and PCB pads once peeled off. This screen is probably pushing the limit of that technology.
Yeah, that was my thought when I heard the riiiiiiip and saw the connectors as well. Oops. I'll still try a few things to see if they can get better and then move on to a new LCD type.
A word of warning on those chinesey esr and capacitance meters - I have the same ones - if the battery is low the accuracy goes completely out the window. You are best off just using the usb socket for powering them. In the low battery charge inaccuracy state they report junk capacitors as good.
Regardless of it's faults from age, it's still a cool looking computer on the outside. Resembles something you'd see in a retro futuristic sci-fi setting.
François FritZ same, I had a Sinclair z88 I thought I’d somehow broken it as nothing came up on the screen. after taking it apart and putting it back together and accidentally touching the contrast wheel i realisedmy mistake
You can try to change the electrolytic caps in the display itself. They are usually quite stressed and worn. This could improve the display quality a little, especially when the content on the screen changes.
The PPC512 should be able to play planet-X3 on the LCD display. I was able to get it running on my 640 (I believe footage of it was shown in one of his videos). So you might need to tweak some of the dip switches, but even with it working the screen ghosting almost makes it unplayable 😉 Great to see more Amstrad PPC videos!
Right. I've been told I had a dip switch set incorrectly (I think the second one?) and that Planet X3 *should* work. I'll try that next when I revisit the PPC, but you're right, the ghosting is sooooo bad that I'm already looking for LCD alternatives.
@@NoelsRetroLab I have mine set to. on, on, on, on, off, on Which should be LCD, CGA, internal GPU, 80column mode. I ended up making a CGA to VGA converter with a TTL converter and GBS board, but I think your RGB solution was better. Its a shame it doesn't have proper composite out, the specs mention having black and white composite on one of the pins but I could never get it to work.
Great video and I am glad you figured out the missing 20 volts. I was thinking you could try using velcro tape to get the back cover part to stay closed.
Great video - I have a PPC 640 dual drive in good order - the LCD is not that good, any games or fast scrolling are quite blurred. It was bought from British reseller Morgan computers but I believe it was originally us market as it came with keycap stickers pre installed from 'new'!
Hi Noel, thanks again for this video. It's makes me happy to see somebody who worked it out til it's runs again. To see schematics of this old computer, reading it and fix it, thank you. About the Zebra stripes: Could you use the other zebra stripes from the defect display? The little smiling as you say "year 2020", I know what you mean and it's all you can say without saying it. I wish you and your family (and the little helper) all the best, and a happy new year 2021 (Feliz año nuevo). See you in 2021.
Thanks! Yes, that was quite weird. The way it was cut I don't think they wanted to reuse it for anything else. Do you have any advice on how to improve the connection of those zebra strips on the LCD? I imagine you have experience with them.
@@NoelsRetroLab Indeed, nice job on the PCB Power side. Nice attempt with LCD as well ! Unfortunately, replacing the zebra strips will be expensive I'm afraid, even though it would be an ideal solution. Such long elastomeric strips have a tendency to shrink with age, especially once removed and put back into place like you did. With 25+ years old strips, chances to have them back perfectly aligned with contacts are low. Some no cost suggestions : I noticed you have cleaned the LCD's PCB and zebra stripes on both sides, but you didn't show on camera if you cleaned the LCD panel's contacts as well. If you didn't, I would strongly suggest to do so, as this might help improving the connection. You can also try taking a pencil eraser to the contacts on the board, then cleaning with alcohol to get rid of the residue from the eraser. Also, you can try shimming between the bezel and the LCD glass (on top of the glass) using a narrow strip of self-adhesive tape. You only really need to shim the edge with the zebra strip. The glass then sits a little closer to the PCB compressing the zebra strip slightly more.
Forgetting to check the contrast again is akin to a rule when working on small engines or cars to diagnose one that doesn't run: Does it have gas in it? Even modern cars can succumb to this most simple of fixes :D
One thing that you should really try is cleaning the contacts also on the LCD side of the elastomeric strip. In theory the elastic nature or the strips should make thise dents irrelevant, but my experience is limited to a Sharp PC-1211 (there is a video about changing its display).
The pads on the glass of the LCS may be hard to spot but they correspnd to the ones on the PCB (the elastomeric strip only connects corresponding pads).
I tried that a bit when I flipped them, but didn't put too much effort into it. I figured that part was clean and flat. What do you recommend for that, plain isoproyl alcohol as well?
Robert Baruch's video, "Fixing ALL the TRS-80 PC-1 computers, part 2" ? th-cam.com/video/S8Vagc0FJK8/w-d-xo.html I was wondering how tightly the PCB has to be pressed/crimped on; Robert seems to lean on it while pressing the tabs down to make it work. (Enough that it has to deform/conform ?) And this is seems consistent with the 'successful'/'temporary' repairs I've done where out of frustration I've definitely applied 'enough' pressure on the successful attempt...
Haha, thank you! Yes, this wasn't supposed to compete with the Amiga, obviously. Honestly, even moving from my Amstrad CPC to a PC in 1989 was a shock. It felt so limited from a graphics and sound point of view in comparison! And that wasn't even an LCD one!
I think that's the purpose of the zebra strips. You can align it any way you want and it'll conduct the signal straight to the LCD (at least that's my understanding).
@@NoelsRetroLab Indeed there are two types: aligned and non-aligned. With aligned connectors, each conductive zone is aligned with the contacts on each side. In this implementation the strip must be aligned precisely with the contacts. In non-aligned connectors, the pitch of the conductive zones are at least 2x that of the contacts, and so multiple conductive zones are present between each contact. That is, the conductive zones on the strip are not dedicated to a specific contact. One benefit is that only an approximate alignment of the strip is needed. In addition the multiple conductive zones provides a level of redundancy.
For the zebra strips maybe you can find a newer panel that's the same size on eBay and take them from that. Or maybe work out what the signals the panel uses are and replace it with a modern panel.
Right. I'm thinking of doing a similar mod to one I've seen online that someone put in a VGA LCD of the same size, and connected to the external video signal with a conversion board (which I already have). Initially I thought that was too much of a departure from the original feel of the machine, but after seeing that LCD... I'm ready for something more modern! 😃
Haha yeah that smearing is about as good as you get on that panel, anything fast motion turns to mush, very crisp for text though, i used to use Microsoft works for DOS for word processing on that specific model back in the 90s.
I am pretty sure Amstrad was popular in France, Spain and a few other countries. I never seen any Amstrad model sold here in Canada. The motherboard has a nice layout.
True. Amstrad was close to non-existant in North America in general. It did quite well in the UK, obviously, and surprisingly was fairly well-known in Australia as well.
Haha, when things aren't great, you don't have much to lose. In the end I fixed one thing and made another one worse. I'll go back to it to see if it can be improved, but I'm already looking for modern, color replacements anyway.
Just an idea, but why not look into changing the LCD out for an equivalent sized LCD for something like a backup (reversing) camera from an addon kit for a car?
Yes, that's the plan at this point. I don't like the qualit of this LCD even if I improve it with backlighting. The trick is finding the correct size one and taking RGB input (or VGA). Not sure what kind of signal car LCDs take. I should research that.
@@NoelsRetroLab If I knew what the diagonal measurement was, I could find one very easily on Ebay with an appropriate adapter setup. I could then forward my findings to you via email.
Nice fix and restoration Noel! Those old LCD screens were so bad 😂 I don't think I've ever seen an Amstrad in real life, it looks likes it means business with all those "vent"-lines and the solid construction. I remember using a special Siemens rugged laptop when I used to work as an automation engineer. It was a special laptop containing all the needed PLC software, it was probably really really expensive. It was definitely some years newer than this Amstrad, but anyway, this video reminded me off that old laptop.
Thanks! But you know what, when you touch it and hold it it feels flimsy and squeeky. I think this is a case were it was made to feel really tough but that's just an image. At least it's not super heavy.
If your still working on that a easy fix that we used for same screen on portable game console is using eraser to clean the zebra connector and lcd part which connects to zebra connector
Did you try and use the strips from the broken LCD? I think they are also called elastomeric strips. I had to deal with them when replacing the LCD for my TRS-80 Pocket Computer. Happy New Year to you and your family!
Not yet because they looked to be in similar shape, but I'll probably try next time along with a couple other suggestions. Did you have any problem with them when you replaced that LCD, or did they work first try?
interresting have you tried looking for a modern replacement for the machine there has to be some display out there that might be able to be repinned to the amstrads own screen connector
With such tiny and important contacts on the screen I would have used DeoXit instead of IPA. I also would change the caps of that board.These videos about the Amstrad are really interesting: keep on.
It has absolutely nothing to be, but some days ago I watched a video repairing a Gameboy with problems on the screen. It has nothing to be, but it's also interesting to see how the contacts are the culprits: th-cam.com/video/iUrolFnAUcc/w-d-xo.html
I would use some brake cleaner to clean the zebra strip contacts and a rubber eraser / fibreglass pen to clean the contacts on the PCB. It just might work. Rubber eraser can clean off the tiny corrosion layer that just a cotton swab will not do.
Brake cleaner? Interesting, I had never heard of that used to clean contacts before. Is that something specific you'd use on the rubber material of the zebra strips? The LCD contacts I did give them a very light pass with a fibreglass pen and then finished them off with the contact cleaner pass (I edited that part out since it wasn't particularly interesting).
@@NoelsRetroLab I used a proper contact cleaner for mechanical switches and contacts (the one that leaves oily residue). But for those static contacts, IMHO nothing beats brake cleaner. In the olden days a technician would use a trichloroethylene to clean contacts and PCBs, but good luck finding this anywhere, this was actually better than brake cleaner. For the most stubborn residues, I also used acetone, but this was only on some PCBs to clean the burned flux off, as acetone would attack lot of plastics. Just a note, I know there is a electronics cleaner that behaves almost exactly as the brake cleaner, but I think it could just be the same stuff in a different bottle, priced 5 times more :)
You could also try youtuber Tech Tangents method 'Easy Plastic Reconstruction & Repair' using baking soda and super-glue. th-cam.com/video/n1meoZaHYZo/w-d-xo.html
I have tried to fix zebra strips on many LCDs and always failed in similar fashion as you. I guess that they have to be a very good alignment which is not possible to do by hand and most importantly I suspect that there was some kind of conductive epoxy applied at the factory to both sides of that zebra strip.
Ah, interesting! I think the alignment isn't an issue because they're designed with a smaller pitch factor than the contacts, so you can align them almost any way. I would also expect contacts to be off in some kind of pattern if it was an alignment issue. But I can see how there could be some kind of sealant that caused much better contact. There was even a riiiiip sound as I lifted the board from the pads.
Was that voltage regulator missing on the Donor too then? I know SMTs are a nightmare anyway but I have a certain bad feeling about those X6 and X6 ICs ... Edit: Those top pins on X6 driver the location of that LCD line and they appear to possible connected to the Caps in the middle .... Using the Mark I eyeball at 1080p HD TH-cam though so YMMV! 🙂 Also @18:38 the bottom zebra line seems to have schmutz above the metal tab right where the line appears! Edit 2: Your DIPs are set to MDA 80, did you try X3 with 2 colour CGA or Hercules?
Exactly. That's the plan. I've seen some mods like that online already, but I'd like to find one that is as cheap as possible (and still has good quality). Looking into it right now.
According to the schematic it should be possible to connect most other types of LCDs of this era to the system. You can try to find a suitable one. It's also possible to use a color-variant. I've done a similar mod to an T5100 which had an awful color LCD and switched to a modern variant without tearing of hell.
That's a really convoluted power circuit. I wonder why they just didn't use a power brick with positive and negative rails but I guess they have some sort of standard power supply and this machine alone isn't enough to have a different one manufactured.
The PPC came with a car cigarette lighter adapter, so I presume they saw it being used in a car? Thats what I did with my PPC640 back in the 80s when I was in tech support....
Do you think it would help if you took out the Zebra strip and placed a thin strip of plastic (or even paper / electrical tape) behind it, to increase the pressure of the contacts against the board?
Do you know if it's possible to change the default language? Reading the manual there are pins near the parallel port. I have an Italian unit and wanted to adjust it to display English
Yes, it's possible! That's actually one of the things I wanted to do in an upcoming video with general upgrades to the PPC. I think they're some jumpers on the MB.
@@NoelsRetroLab I can confirm the pins do exist and if you refer to the service manual its a little confusing. Least it was to me, as I couldn't figure out the values until my friend pointed out it was in binary. I've since been able to convert an Italian unit back to English. The PPC bios stores about 7 different languages. Additionally, my PPC512 came with an aftermarket, backlit installed. Providing a nice Casio like, blue backlit effect to the display.
What kind of monitor does it use? Because if it' s a "Hercules", *maybe* you could use a utility like SIMCGA, or something, in order to be able to run CGA games. Or just use a DOS command, like "mode co80", or something. As far as I remember from my school years...
Internally it's MDA only, which looks to be a text-only mode. Hercules was a step up from what I can remember. The MDA card supposedly does CGA emulation, but apparently it only works in some games. Disappointing.
It depends on the type of rubber used but maybe you could try sanding that zebra strip flat with some fine sandpaper. You have 2 of these so there is not much to lose. Maybe freezing it would make it a little bit stiffer and easier to work with.
That's a good idea. It would make them a little shorter, but I think I can put enough pressure in the back that they may make good contact. I'll try that maybe with those or the spare LCD. Chances are that I'm going to replace the whole LCD anyway, so nothing to lose. Thanks for the tip!
0:37 has the signals for the LCD, looks like it may be similar to a parallel port LCD module addressed in 4 bit mode (probably uses a similar chipset). It looks like some of the signals for the RGBi output can be accessed from the LCD connector and with a few bodges to get the H + V sync on there you could convert it to a colour LCD and set the dip switches to output RGB. you would need an LCD screen around the same size and get it to work with the digital RGBi signalling
You obviously love this thing may more than I ever could. I can't get past the fact that it was technologically cheap and unnecessarily backwards in a way that felt like an insult to informed consumers even when it came out. In short, it really was Eighties pirate Alan Sugar's proverbial "mug's eyeful". Granted, (pre-takeover) Sinclair too was dirt cheap, but that was clever cheapness with a purpose; cheapness as a hack. The only sense in which Sugar's semi-compatible PCs also used cheapness as a hack was in it being a hack to make Alan Sugar rich by pulling a fast one on unwary consumers. The early Amstrad PC1512s may have been a genuinely good deal, but by the time these PPC512s came out, they were just yesterday's tech repackaged, offering the same or worse performance than before. This while the rest of the PC world was moving fast. The PPC512 was a semi-compatible poor XT clone released the year between the arrival of 386 and 486 PCs. Still, if this machine had a special place in your past, then I can understand the nostalgia. I will admit that the physical packaging was unique and interesting, but they should at least have gone with 100% IBM-compatible 286 innards. It probably wouldn't have been that much dearer to do so, since a lot of the money was spent on engineering the case, etc.
I bought the PPC640 from Computer Shopper because it was very affordable compared to similarly configured computers. In fact, for the day, it came with extras. A full-sized keyboard. A built-in screen (no need to buy monitor. 2400bps modem (fast!). Two disk drives! 720k disk drives! Full complement of software. Yes, it was not the best constructed, but as a young person right out of college just starting out it gave me a home computer in 1983. Spent many hours on BBSs and Sears JUMP service on this. Also, CompuServ and GEnie.
Right! I wasn't familiar with that configuration, and it was hard to figure out from the voltage-generation circuit the way it was layed out, but eventually it made sense.
Acrylic two component cement is best for ABS, type for dentures reparation, used for decades. Problem is only if there is just to much polycarbonate in plastics ABS+PC blend
The black "line" down the center of the rubber "zebra" strip is actually hundreds of tiny, but separate, conductive vertical lines that connect the top to the bottom. Think of it like a row of vertical wires set into a block of rubber. There are actually many more conductors than needed, to allow for the rubber strip to be positioned easily. Each circuit board trace touches 2-5 (this can vary based on trace size and zebra strip) of the vertical conductors, with a few unused ones between each contact. As long as the traces on the circuit board and the traces on the glass contact some of the same vertical conductors, the circuit will be complete.
@@TheErador O.K. Just a thought, I can't realy see any other way it could break. Unless there was something sitting on the screen when the keyboard was shut.
Yeah, I don't think that was it. I'm inclined to think it was either a) a very frustrated user taking it out on the computer or b) a heavy object (flower pot?) falling when the screen was folded in. Given the quality of the LCD I'm starting to think it was a 😃
I used one of these extensively back in the day, and it definitely supported CGA graphics on the LCD. Any chance you need to fiddle with the dip switches?
Did it work for everything? I did a quick search and it seems that only some games work under CGA emulation. I did fiddle with the pins a bit, and if I set it to CGA the LCD displays absolutely nothing, even in normal start up mode.
@@NoelsRetroLab Obviously it's been a long time, but I don't remember any issues with ANYTHING not working in CGA mode. In particular I was very into fractals at the time and I spent a lot of time running Fractint in CGA graphics mode (which yes, was a pretty horrific experience, but it worked!). For what it's worth this technical reference, which you may already have seen, indicates that it is completely CGA compatible: www.seasip.info/AmstradXT/ppctech/section1.html#1.11 There are also a bunch of other reviews and resources indicating CGA compatibility. It's actually a very standard hardware CGA implementation, not like the Amstrad PC1520 and 1640 which were indeed pretty eccentric. The behaviour you showed is exactly what I would expect if the unit was configured for MDA not CGA. Anyway, I absolutely promise that Fractint in CGA 640x200 mode should definitely work, and if it doesn't there's either a misconfiguration or a hardware fault.
Really late to the party with this comment, but why is no-one making a Li-Ion battery pack to go into the battery bay for this? Doesn't have to be chargable in situ, basically the innards of a powerbank, sized accordingly and with a 12v output? How many 18650 cell can we get in there? :-)
You could try to use some sandpaper to smooth out the surface of those conductive rubber strips from the panel. just make sure you glue the sand paper to a flat and rigid surface, it might work, you got an extra one to experiment with, right?
omg what you have done? cleaning display contact gum with isopropyl alcohol? gum will expand and contacts will be misplaced, the only repair is wait till it dry and pray if it fits again properly :)
This is the kind of connector that doesn't need to be aligned properly. That's the big advantage of it and why it's used there. As a matter of fact, one of the things I'm going to try is to soak it in warm water to expand it and see if it regains some of the volume and elasticity that it used to have 30 years ago.
Dude, you know you don't have to replace the cap with another 100uF 63V right? Anything with approximately the same capacitance, 63V or higher, will be fine. It probably won't even matter if the capacitance is higher, it's only there to buffer the power. They certainly make capacitors that are suitable. You could even pair up two 50uF caps if you liked. You could even get away with lower than 63V, that's just a margin of error cos electronic engineers like to use those where they can. Trying to replace it with another 30 year old cap from a *broken* brother isn't the brightest idea. Probably lots of caps in both machines are right on the edge of functioning, it's only because electrolytics are usually used as buffers, that circuits can cope with them almost completely failing and still carry on.
I suggest you get some kind of component tester from aliexpress for a few euro. Thats probably better than only measuring the ESR. Just search for GM328.
@@NoelsRetroLab It measures the ESR too, maybe not as accurate as your ESR meter, but I think it's good enough. The good thing is that they measure the capacitance too. If it's not within tolerance it's probably a good idea to replace it. A slightly higher ESR almost never causes any problems in a circuit. But hey, I'm a hobbyist, so my knowlegde is limited.
I remember the ghosting from my PPC 640 which I bought new in 1988. Amazingly, as I didn't know any better, I got used to it.
Your best option is probably to heat the zebra strips up with hot water or something like that. The rubber material needs some heat to wake up the elastomer and get it to go back to the shape it was molded in.
Oh interesting! I didn't realize that. That's the perfect thing to experiement with the extra set from the other LCD. Someone also suggested the opposite: freezing them to make them harder and sanding them down. I can see trying both approaches.
@@NoelsRetroLab Sanding them down is going to be really difficult because the surface needs to be very flat that there's no good way to fixture them to ensure flatness. Boiling them in water for twenty or thirty minutes with just a dab of baby shampoo or similar salt-free detergent is probably the first thing I'd try. Then wash them with distilled water and let them dry out thoroughly before reassembling.
@@NoelsRetroLab I'd also wait for a while before trying to do anything with the zebra strips. I've had those come good after just sitting for a while (around a week or so). I'm not sure if it's the viscoelasticity of the material at play or evaporation of the cleaning compounds I've used or what. Anyway, it just costs a bit of time to see.
@@NoelsRetroLab I could really see this working. I know for example that "rubber" suction cups that hold thins in an aquarium get really stiff and hard after some years - but boiling them in water restores the elasticity and they magically work again.
I appreciate the thoughtful and straightforward way you approached the LCD’s power problem. It’s inspiring to watch someone carefully work through a problem.
Thank you so much!
Thank you for this video! I had exactly same issue with my ppc512 bought 20 years ago! It was so worth to keep it all this time to find this video! Screen does work now! Thank you!
Crazy that it was the same problem! Glad it helped! 👍
I was thinking 'adjust the screen controls!' when the screen wasn't working after the 7905 replacement. Great to see you got it working!
Haha, yes! People were already yelling that at the screen last video. Fortunately I DID test it last time, so I wasn't a total moron 😃
Excellent Video, I just dug my Amstrad PPC512 out of storage and fired it up. Still works perfectly on the original power supply. Only used it for about a year in the field, but was never willing to toss it, even after many many moves, thought it looked cool.
What's nice, is the room on top for you to plop a proper colour monitor when you're at home / work.
@@greenaum Guess you could but I used my Amstrad strictly in the field for downloading data from exploration equipment and putting it on floppy disk. Then in the office transfering the data from floppy to a faster computer with a nice size screen.
You could try a small magnet for the port cover? There are already round spaces for a magnet.
Yes, that's a good idea. And there's a round space already?? I missed that!! 😃
I was thinking the exact same thing.
Adhesive backed velcro might work too with a bit in the corner at the top or both top corners if required. It probably isn't going to be opened on a regular basis and is easily "undone" if need be.
A more generic name for "Zebra strip" is elastomeric connector. If you can find one that is the right thickness you can probably just cut it to length. The LCD is absolutely terrible though. It would be nice to replace it with a more modern LCD, but I am not sure the interface is standard. Probably not.
Excellent video as usual. Happy next year Noel!
Right. I had seen that but thanks for confirming that. I agree that the LCD is horrible, and the final straw is that the MDA mode has horrible CGA emulation so... off to get a new LCD!
Noel, As I mentioned on the first PPC 512 video I used to fit backlights to these PPC screens (& HDDs in the 2nd floppy Bay). To get the screen perfect you need to manipulate it very, very gently when it is half assembled. So, loosen/undo all the tabs on the back of the screen except a couple top & bottom then with the power on and screen connected, very very gently slide the screen left and right, up and down until you see a perfect picture. Your movements will be tiny (and there was definitely a knack to it) but by moving it you can align all those connections properly. Then carefully re-twist all the other tabs checking all the time the alignment is correct. There is no way to do it without the screen on and working! Happy new year, RR
Connor Hard Drives with the controllers integrated?
@@Fezzler61 Yes they were Connor drives 20 & 30Mb I think. It was 30 years ago!
I would fill up that broken handle with epoxy around the screw posts, There‘s a lot of unnecessary space that was left only to make the part cheaper and it would make it really sturdy if these posts had support all around them.
That's a great idea, Markus! I'll definitely do that. Thanks for the tip!
I remember taking one of those home from work to show off a portable PC to my family lol
Haha, well, back then it was definitely show-offable 😃 And then, if you connect to the Internet with it... minds blown!
Suggestion for the broken door hinge ... A hobby store should have small hollow plastic spacers / tubes. One of the right diameter and thickness could be cut to the needed length, then in half (or as required) to complete the hinge. When gluing the half in place, use just a little superglue and keep the hinge moving slightly while the superglue initially sets to avoid any seepage from the joint accidentally gluing to the axle (I speak from negative experience with plastic models 😉). This will not fix the clip part ... but I saw an excellent suggestion about Velcro for that.
Noel for the ports panel it might be cool to mount small magnets on the inside of the panel to hold it closed so it’s not “flopping in the wind” as Dave from EEV Blog might say. I think I saw Adrian Black do this for one of his builds but don’t quote me on that... might have been rare earth magnets he used too.. Happy New Year
Yes, good idea. I'll look into doing something like that. Thanks and happy new year!
Amazing video Noel, such a fascinating video and computer.
Very cool indeed, stay safe.
thank you for your 2 Videos about PPC512, i bought last week one, and he works fine hope ;)
at first , i had to search an DD DOS 3.2 Disk ;)
Great part of computer history. This video is awesome
Glad you think so!
Great video as always! If you want to go the extra mile to fix that hinge, Shelby from TT has a pretty good method of reconstructing plastic with superglue and baking soda, if I recall correctly he used it for an hinge as well.
Yes, I saw that! That was one of my first thoughts, but that requires removing the whole door and I chickened out 😃
Thanks Noel for another great video, and a great year. You guys have helped us through a difficult year, you deserve the subscription growth. 10k plus. Congrats.
Nice job! The Amstrad without its LCD display isn't really the way we remember. :)
4:00 re: the power jack, I was just working on a B&W TV and also found the solder joint cracked on the DC power barrel jack. Perhaps using the electrical connections as a mechanical fastener for a power jack is unreliable after much use. I decided to additionally use some plastic epoxy to attach a new jack to the PCB.
Dry joints on the barrel jack also happen on the Amstrad CPC 464 quite a bit as well. Probably too much pressure and repeated use.
Have seen a few videos where they glue a small magnet to one side of a flap and a bit of metal if needed to the other side to fix broken locking clips
Glad you got it working. Well done! 👍🕹️
Your friend in retro, Perifractic
Thanks! It wasn't perfect, but it's kind of working. Now I have my usual "problem" of not wanting to stop once I get going with a particular machine, so I'm going to upgrade it and then try to replace the LCD altogether with something much better. Should be quite fun!
@@NoelsRetroLab Yeah I'd love to see a clearer display on that. 👍🕹️
Nice one Noel! Just recieved a PPC512 to work on myself and remembered your video.
I am curious to see how you get on with that "zebra strip". I have never been able to improve issues when those things are involved but I never replaced them.
THANK YOU for your videos, I am always happy to watch them! Happy new year too Noel!
I'm already looking into LCD replacements, but I might go back and try a few things on the zebra strips just for completeness and experimenting. Thank you and happy new year to you too!
A little bit of pressure might fix the LCD. I know pressing didn't help but even pressure along it can. Some paper wedged in is all you need.
Thought the same
In new year, my sincere wishes to your family to have a fruitful time, stay healthy and keep a smile fired up for more beautiful restorations
Thank you so much! Happy new year to you and your family as well! 🎉
When I saw those zebra strips I thought, "oh no". I haven't had a lot of luck getting those things to simultaneously contact the LCD glass conductors and PCB pads once peeled off. This screen is probably pushing the limit of that technology.
Yeah, that was my thought when I heard the riiiiiiip and saw the connectors as well. Oops. I'll still try a few things to see if they can get better and then move on to a new LCD type.
Only "hotmelt" is worse. Those ALWAYS fail just from getting old.
A word of warning on those chinesey esr and capacitance meters - I have the same ones - if the battery is low the accuracy goes completely out the window. You are best off just using the usb socket for powering them. In the low battery charge inaccuracy state they report junk capacitors as good.
Oh interesting! I didn't know low battery would make that big of a difference. I'll keep it in mind. Thanks!
Regardless of it's faults from age, it's still a cool looking computer on the outside. Resembles something you'd see in a retro futuristic sci-fi setting.
Absolutely cool and sci-fi looking!
since the first video im crying " touch the contrast knobe!!!" happy new year.
François FritZ same, I had a Sinclair z88 I thought I’d somehow broken it as nothing came up on the screen. after taking it apart and putting it back together and accidentally touching the contrast wheel i realisedmy mistake
@@xandercrawin my case, im just a gameboy owner
You heard me when I yelled "Contrast"! LOL
I felt a great disturbance in the Force, as if millions of voices cried out and yelled "CONTRAST"! 😃
Very good as usual. Keep up the great work, sir!
Thank you very much! 👍
You can try to change the electrolytic caps in the display itself. They are usually quite stressed and worn. This could improve the display quality a little, especially when the content on the screen changes.
Good point! I didn't think of them affecting the LCD quality, but it's possible. 👍
The PPC512 should be able to play planet-X3 on the LCD display. I was able to get it running on my 640 (I believe footage of it was shown in one of his videos).
So you might need to tweak some of the dip switches, but even with it working the screen ghosting almost makes it unplayable 😉
Great to see more Amstrad PPC videos!
Right. I've been told I had a dip switch set incorrectly (I think the second one?) and that Planet X3 *should* work. I'll try that next when I revisit the PPC, but you're right, the ghosting is sooooo bad that I'm already looking for LCD alternatives.
@@NoelsRetroLab I have mine set to.
on, on, on, on, off, on
Which should be LCD, CGA, internal GPU, 80column mode.
I ended up making a CGA to VGA converter with a TTL converter and GBS board, but I think your RGB solution was better.
Its a shame it doesn't have proper composite out, the specs mention having black and white composite on one of the pins but I could never get it to work.
Great video and I am glad you figured out the missing 20 volts. I was thinking you could try using velcro tape to get the back cover part to stay closed.
Thanks! Yes, that or a small magnet. That's a good idea.
I have exactly the same unit sat waiting for some tlc. Fortunately mine works but needs some love. May have to dig it out!
You should! It's fun to restore them 😃
Great video - I have a PPC 640 dual drive in good order - the LCD is not that good, any games or fast scrolling are quite blurred. It was bought from British reseller Morgan computers but I believe it was originally us market as it came with keycap stickers pre installed from 'new'!
most morgan stuff I found not worth the saving, unfortunatley
Hi Noel, thanks again for this video. It's makes me happy to see somebody who worked it out til it's runs again. To see schematics of this old computer, reading it and fix it, thank you.
About the Zebra stripes: Could you use the other zebra stripes from the defect display?
The little smiling as you say "year 2020", I know what you mean and it's all you can say without saying it.
I wish you and your family (and the little helper) all the best, and a happy new year 2021 (Feliz año nuevo). See you in 2021.
Excellent job working out the power issue! Maybe someone stole the 7905 off it to fix something else?!? Very strange!
Thanks! Yes, that was quite weird. The way it was cut I don't think they wanted to reuse it for anything else.
Do you have any advice on how to improve the connection of those zebra strips on the LCD? I imagine you have experience with them.
@@NoelsRetroLab The regulator might have vibrated off it's legs.
@@NoelsRetroLab Indeed, nice job on the PCB Power side. Nice attempt with LCD as well !
Unfortunately, replacing the zebra strips will be expensive I'm afraid, even though it would be an ideal solution.
Such long elastomeric strips have a tendency to shrink with age, especially once removed and put back into place like you did. With 25+ years old strips, chances to have them back perfectly aligned with contacts are low.
Some no cost suggestions :
I noticed you have cleaned the LCD's PCB and zebra stripes on both sides, but you didn't show on camera if you cleaned the LCD panel's contacts as well.
If you didn't, I would strongly suggest to do so, as this might help improving the connection.
You can also try taking a pencil eraser to the contacts on the board, then cleaning with alcohol to get rid of the residue from the eraser.
Also, you can try shimming between the bezel and the LCD glass (on top
of the glass) using a narrow strip of self-adhesive tape. You only really need to shim the edge with the zebra strip. The glass then sits a little closer to the PCB compressing the zebra strip slightly more.
Is it possible to like with old rubber belts gently heat the zebra stripping in water to reform it
Forgetting to check the contrast again is akin to a rule when working on small engines or cars to diagnose one that doesn't run: Does it have gas in it?
Even modern cars can succumb to this most simple of fixes :D
Haha, totally! I'm glad I caught myself within a few seconds or it would have been quite embarrassing! 😃
Happy New Year Noel, and congratulations on growing such an awesome channel. Really entertaining and informative.
One thing that you should really try is cleaning the contacts also on the LCD side of the elastomeric strip. In theory the elastic nature or the strips should make thise dents irrelevant, but my experience is limited to a Sharp PC-1211 (there is a video about changing its display).
The pads on the glass of the LCS may be hard to spot but they correspnd to the ones on the PCB (the elastomeric strip only connects corresponding pads).
I tried that a bit when I flipped them, but didn't put too much effort into it. I figured that part was clean and flat. What do you recommend for that, plain isoproyl alcohol as well?
Robert Baruch's video, "Fixing ALL the TRS-80 PC-1 computers, part 2" ?
th-cam.com/video/S8Vagc0FJK8/w-d-xo.html
I was wondering how tightly the PCB has to be pressed/crimped on; Robert seems to lean on it while pressing the tabs down to make it work. (Enough that it has to deform/conform ?) And this is seems consistent with the 'successful'/'temporary' repairs I've done where out of frustration I've definitely applied 'enough' pressure on the successful attempt...
Merry Christmas and Happy New Year! I'd definitely upgrade that screen if possible. It would make the machine that much more enjoyable.
Thank you! Yes, I think so too. Happy new year!
Kudos Noel :) Even i dont understand who can love these LCD Amstrads :) Thank god i had Amiga back in the days
Haha, thank you! Yes, this wasn't supposed to compete with the Amiga, obviously. Honestly, even moving from my Amstrad CPC to a PC in 1989 was a shock. It felt so limited from a graphics and sound point of view in comparison! And that wasn't even an LCD one!
The negative BIAS voltage on those kind of LCDs is responsible for the contrast control...
Oh interesting! So I was effectively running it with minimum contrast with just -15V! That makes a lot of sense.
Maybe you should replace all the capacitors. You should re-solder all the contacts on the socket.
did he put back the bad ESR cap?
I'm amazed how the LCD's metal frame and the PCB's dimensions are expected to adequately align those tiny LCD contact pads.
I think that's the purpose of the zebra strips. You can align it any way you want and it'll conduct the signal straight to the LCD (at least that's my understanding).
@@NoelsRetroLab Indeed there are two types: aligned and non-aligned. With aligned connectors, each conductive zone is aligned with the contacts on each side. In this implementation the strip must be aligned precisely with the contacts.
In non-aligned connectors, the pitch of the conductive zones are at least 2x that of the contacts, and so multiple conductive zones are present between each contact. That is, the conductive zones on the strip are not dedicated to a specific contact. One benefit is that only an approximate alignment of the strip is needed. In addition the multiple conductive zones provides a level of redundancy.
Thank you for this great content. Happy Holidays everyone!
For the zebra strips maybe you can find a newer panel that's the same size on eBay and take them from that. Or maybe work out what the signals the panel uses are and replace it with a modern panel.
Right. I'm thinking of doing a similar mod to one I've seen online that someone put in a VGA LCD of the same size, and connected to the external video signal with a conversion board (which I already have). Initially I thought that was too much of a departure from the original feel of the machine, but after seeing that LCD... I'm ready for something more modern! 😃
Haha yeah that smearing is about as good as you get on that panel, anything fast motion turns to mush, very crisp for text though, i used to use Microsoft works for DOS for word processing on that specific model back in the 90s.
I am pretty sure Amstrad was popular in France, Spain and a few other countries.
I never seen any Amstrad model sold here in Canada. The motherboard has a nice layout.
True. Amstrad was close to non-existant in North America in general. It did quite well in the UK, obviously, and surprisingly was fairly well-known in Australia as well.
That was quite a courage trying to fix LCD, I would be afraid to kill it completely. 👍
Haha, when things aren't great, you don't have much to lose. In the end I fixed one thing and made another one worse. I'll go back to it to see if it can be improved, but I'm already looking for modern, color replacements anyway.
Just an idea, but why not look into changing the LCD out for an equivalent sized LCD for something like a backup (reversing) camera from an addon kit for a car?
Yes, that's the plan at this point. I don't like the qualit of this LCD even if I improve it with backlighting. The trick is finding the correct size one and taking RGB input (or VGA). Not sure what kind of signal car LCDs take. I should research that.
@@NoelsRetroLab If I knew what the diagonal measurement was, I could find one very easily on Ebay with an appropriate adapter setup. I could then forward my findings to you via email.
Nice fix and restoration Noel! Those old LCD screens were so bad 😂 I don't think I've ever seen an Amstrad in real life, it looks likes it means business with all those "vent"-lines and the solid construction. I remember using a special Siemens rugged laptop when I used to work as an automation engineer. It was a special laptop containing all the needed PLC software, it was probably really really expensive. It was definitely some years newer than this Amstrad, but anyway, this video reminded me off that old laptop.
Thanks! But you know what, when you touch it and hold it it feels flimsy and squeeky. I think this is a case were it was made to feel really tough but that's just an image. At least it's not super heavy.
@@NoelsRetroLabOh really?! So it's just tough on the Internet like all the trolls in comment sections :)
Happy holidays my friend. Thanks for the useful videos. Take care..
If your still working on that a easy fix that we used for same screen on portable game console is using eraser to clean the zebra connector and lcd part which connects to zebra connector
Interesting! I hadn't seen that trick before. Just a regular eraser, not an ink one? I should try that. Thanks!
@@NoelsRetroLab yes regular one.
most people in who deal in electronics use it to clean contact of ram or other such things
Did you try and use the strips from the broken LCD? I think they are also called elastomeric strips. I had to deal with them when replacing the LCD for my TRS-80 Pocket Computer. Happy New Year to you and your family!
Not yet because they looked to be in similar shape, but I'll probably try next time along with a couple other suggestions. Did you have any problem with them when you replaced that LCD, or did they work first try?
@@NoelsRetroLab for me they worked first try. I used ipa to clean both sides and also cleaned the context on the LCD itself.
Nice video and great work on that Greetings from CPUGALAXY
interresting have you tried looking for a modern replacement for the machine there has to be some display out there that might be able to be repinned to the amstrads own screen connector
Yes, I've been researching that and I already have one sitting on my workbench. I just need to try to connect everything together 😃
@@NoelsRetroLab awesome
With such tiny and important contacts on the screen I would have used DeoXit instead of IPA. I also would change the caps of that board.These videos about the Amstrad are really interesting: keep on.
I would fear that DeoXit might eat away on the LCD glass contacts .. they are as thin as a layer of oxyd I imagine. would it really be safe to use it?
It has absolutely nothing to be, but some days ago I watched a video repairing a Gameboy with problems on the screen. It has nothing to be, but it's also interesting to see how the contacts are the culprits: th-cam.com/video/iUrolFnAUcc/w-d-xo.html
I would use some brake cleaner to clean the zebra strip contacts and a rubber eraser / fibreglass pen to clean the contacts on the PCB. It just might work. Rubber eraser can clean off the tiny corrosion layer that just a cotton swab will not do.
Brake cleaner? Interesting, I had never heard of that used to clean contacts before. Is that something specific you'd use on the rubber material of the zebra strips? The LCD contacts I did give them a very light pass with a fibreglass pen and then finished them off with the contact cleaner pass (I edited that part out since it wasn't particularly interesting).
@@NoelsRetroLab I used a proper contact cleaner for mechanical switches and contacts (the one that leaves oily residue). But for those static contacts, IMHO nothing beats brake cleaner. In the olden days a technician would use a trichloroethylene to clean contacts and PCBs, but good luck finding this anywhere, this was actually better than brake cleaner. For the most stubborn residues, I also used acetone, but this was only on some PCBs to clean the burned flux off, as acetone would attack lot of plastics. Just a note, I know there is a electronics cleaner that behaves almost exactly as the brake cleaner, but I think it could just be the same stuff in a different bottle, priced 5 times more :)
Excelente video, como todos.
Feliz año
How about a small piece of beige velcro to hold the ports panel closed?
Yes, that would be better than it is now, wouldn't it? I've also seen suggested using a small magnet.
I thought the same! ;-)
Magnet is better than velcro, velcro will put too much stress on already aging plastic imho
You could also try youtuber Tech Tangents method 'Easy Plastic Reconstruction & Repair' using baking soda and super-glue.
th-cam.com/video/n1meoZaHYZo/w-d-xo.html
Maybe a bit of conductive paint or adding some carbon (with a pencil?) might help with that strip. Or maybe it can be sanded down slightly?
I have tried to fix zebra strips on many LCDs and always failed in similar fashion as you. I guess that they have to be a very good alignment which is not possible to do by hand and most importantly I suspect that there was some kind of conductive epoxy applied at the factory to both sides of that zebra strip.
Ah, interesting! I think the alignment isn't an issue because they're designed with a smaller pitch factor than the contacts, so you can align them almost any way. I would also expect contacts to be off in some kind of pattern if it was an alignment issue. But I can see how there could be some kind of sealant that caused much better contact. There was even a riiiiip sound as I lifted the board from the pads.
Was that voltage regulator missing on the Donor too then?
I know SMTs are a nightmare anyway but I have a certain bad feeling about those X6 and X6 ICs ...
Edit: Those top pins on X6 driver the location of that LCD line and they appear to possible connected to the Caps in the middle .... Using the Mark I eyeball at 1080p HD TH-cam though so YMMV! 🙂
Also @18:38 the bottom zebra line seems to have schmutz above the metal tab right where the line appears!
Edit 2: Your DIPs are set to MDA 80, did you try X3 with 2 colour CGA or Hercules?
Thanks and have a great New Year Noel!
Thanks! Happy new year!
I wonder if it's possible to replace the LCD with a more modern model, then provide video for it from the CGA/EGA port?
Exactly. That's the plan. I've seen some mods like that online already, but I'd like to find one that is as cheap as possible (and still has good quality). Looking into it right now.
@@NoelsRetroLab Do I remember from years ago the PS ONE portable screen is a candidate for replacement?
Has I remember pc1512 has a slightly diferent graphic circuit something between CGA and EGA.
According to the schematic it should be possible to connect most other types of LCDs of this era to the system. You can try to find a suitable one. It's also possible to use a color-variant. I've done a similar mod to an T5100 which had an awful color LCD and switched to a modern variant without tearing of hell.
Yeah, I'm looking into replacing it with a modern color one actually. Interfacing gets trickier, but it's definitely doable 👍
Nice Work. Happy New Year to ALL, from Karachi, Pakistan.
Thank you! Happy new year to you too!
Rubber strips off the old LCD?
I haven't tried them, but visually they're exactly the same. Still, good to have an extra pair for experiments.
good to see progress on the amstrad. was this computer named after one of alans workers?
Thanks! This one was just Portable PC. Maybe you're thinking of the nickname "Arnold" for the CPC, which supposedly was for one of the designers.
@@NoelsRetroLab I had heard the PCW was Joyce. I wonder if all there computers had names
Little magnet and steel plate for the panel that doesn't stay closed?
Yeah, good idea. I'll try that next time.
That's a really convoluted power circuit. I wonder why they just didn't use a power brick with positive and negative rails but I guess they have some sort of standard power supply and this machine alone isn't enough to have a different one manufactured.
No idea! Amstrad also had some convoluted power supply in the GX4000, although not as bad as this.
The PPC came with a car cigarette lighter adapter, so I presume they saw it being used in a car? Thats what I did with my PPC640 back in the 80s when I was in tech support....
Don't forget that it can also run off of batteries, so it needed to have an internal power supply.
Do you think it would help if you took out the Zebra strip and placed a thin strip of plastic (or even paper / electrical tape) behind it, to increase the pressure of the contacts against the board?
Not behind it because it needs to conduct the signal to the LCD itself.
@@NoelsRetroLab Ah of course!
Do you know if it's possible to change the default language? Reading the manual there are pins near the parallel port. I have an Italian unit and wanted to adjust it to display English
Yes, it's possible! That's actually one of the things I wanted to do in an upcoming video with general upgrades to the PPC. I think they're some jumpers on the MB.
@@NoelsRetroLab I can confirm the pins do exist and if you refer to the service manual its a little confusing. Least it was to me, as I couldn't figure out the values until my friend pointed out it was in binary. I've since been able to convert an Italian unit back to English. The PPC bios stores about 7 different languages. Additionally, my PPC512 came with an aftermarket, backlit installed. Providing a nice Casio like, blue backlit effect to the display.
Thank you for this great channel!!!!
Glad you enjoy it! 👍
What kind of monitor does it use? Because if it' s a "Hercules", *maybe* you could use a utility like SIMCGA, or something, in order to be able to run CGA games. Or just use a DOS command, like "mode co80", or something. As far as I remember from my school years...
Internally it's MDA only, which looks to be a text-only mode. Hercules was a step up from what I can remember. The MDA card supposedly does CGA emulation, but apparently it only works in some games. Disappointing.
Very interesting, You have a New subscriber!!
Awesome, thank you!!
It depends on the type of rubber used but maybe you could try sanding that zebra strip flat with some fine sandpaper. You have 2 of these so there is not much to lose. Maybe freezing it would make it a little bit stiffer and easier to work with.
That's a good idea. It would make them a little shorter, but I think I can put enough pressure in the back that they may make good contact. I'll try that maybe with those or the spare LCD. Chances are that I'm going to replace the whole LCD anyway, so nothing to lose. Thanks for the tip!
I fear that sanding would spead the conducting material between the dots making the elastomeric strip unusable.
@@giacintoboccia9386 Yeah, there is such posibility. But I think it's still worth the try.
Happy New Year, Noel :)
Happy new year to you too!!
Wow man.
Hi Noel! Why not try to adapt some modern LCD panel that can support all the CGA modes? Anyway, I want to wish you a happy new year!
Yes, that's what I'm thinking about. It would need to take some kind of RGB input ideally and fit right in the frame. Let's see what I can find!
I guess the minus 20V is just for the contrast of the display...
I haven't looked at the internals of the LCD circuit, but that makes a lot of sense.
try zebra connectors from broken screen .
They looked to be in very similar condition, but I'll try that next time.
why you didn't test the zebra strips from broken lcd?? they could have been better.
That is actually a nice idea, I was saying get another LCD but that should work because it has the same indentations
can't you just mod it with more modern lcd? even a color one in BW config?
0:37 has the signals for the LCD, looks like it may be similar to a parallel port LCD module addressed in 4 bit mode (probably uses a similar chipset). It looks like some of the signals for the RGBi output can be accessed from the LCD connector and with a few bodges to get the H + V sync on there you could convert it to a colour LCD and set the dip switches to output RGB. you would need an LCD screen around the same size and get it to work with the digital RGBi signalling
@@williefleete so it's doable
You obviously love this thing may more than I ever could. I can't get past the fact that it was technologically cheap and unnecessarily backwards in a way that felt like an insult to informed consumers even when it came out. In short, it really was Eighties pirate Alan Sugar's proverbial "mug's eyeful". Granted, (pre-takeover) Sinclair too was dirt cheap, but that was clever cheapness with a purpose; cheapness as a hack. The only sense in which Sugar's semi-compatible PCs also used cheapness as a hack was in it being a hack to make Alan Sugar rich by pulling a fast one on unwary consumers. The early Amstrad PC1512s may have been a genuinely good deal, but by the time these PPC512s came out, they were just yesterday's tech repackaged, offering the same or worse performance than before. This while the rest of the PC world was moving fast. The PPC512 was a semi-compatible poor XT clone released the year between the arrival of 386 and 486 PCs. Still, if this machine had a special place in your past, then I can understand the nostalgia. I will admit that the physical packaging was unique and interesting, but they should at least have gone with 100% IBM-compatible 286 innards. It probably wouldn't have been that much dearer to do so, since a lot of the money was spent on engineering the case, etc.
I bought the PPC640 from Computer Shopper because it was very affordable compared to similarly configured computers. In fact, for the day, it came with extras. A full-sized keyboard. A built-in screen (no need to buy monitor. 2400bps modem (fast!). Two disk drives! 720k disk drives! Full complement of software. Yes, it was not the best constructed, but as a young person right out of college just starting out it gave me a home computer in 1983. Spent many hours on BBSs and Sears JUMP service on this. Also, CompuServ and GEnie.
A bunch of diodes and capacitors that turns -15 into -30? That's a charge pump alright. No wonder it didn't work without a proper bias. :)
Right! I wasn't familiar with that configuration, and it was hard to figure out from the voltage-generation circuit the way it was layed out, but eventually it made sense.
Hi Noel, have you looked into the baking soda and superglue technique for rebuilding plastic hinges or clips that have broken?
Acrylic two component cement is best for ABS, type for dentures reparation, used for decades.
Problem is only if there is just to much polycarbonate in plastics ABS+PC blend
could you use conductive paint pen on that lcd set of strips?
The black "line" down the center of the rubber "zebra" strip is actually hundreds of tiny, but separate, conductive vertical lines that connect the top to the bottom. Think of it like a row of vertical wires set into a block of rubber. There are actually many more conductors than needed, to allow for the rubber strip to be positioned easily. Each circuit board trace touches 2-5 (this can vary based on trace size and zebra strip) of the vertical conductors, with a few unused ones between each contact. As long as the traces on the circuit board and the traces on the glass contact some of the same vertical conductors, the circuit will be complete.
@@dnwheeler thanks for the explanation... it looked like one continuous strip
I was wondering if the keyboard got pushed into the screen to break it? The ghosting is always there on those types of screen. Happy New Year, Noel.
Nah it sits quite low in the frame iirc
@@TheErador O.K. Just a thought, I can't realy see any other way it could break. Unless there was something sitting on the screen when the keyboard was shut.
Yeah, I don't think that was it. I'm inclined to think it was either a) a very frustrated user taking it out on the computer or b) a heavy object (flower pot?) falling when the screen was folded in. Given the quality of the LCD I'm starting to think it was a 😃
Sounds likely, Noel. I was never rough with our one, but equally didn't treat it with kid gloves. They can take a reasonable amount of battering.
I used one of these extensively back in the day, and it definitely supported CGA graphics on the LCD. Any chance you need to fiddle with the dip switches?
Did it work for everything? I did a quick search and it seems that only some games work under CGA emulation. I did fiddle with the pins a bit, and if I set it to CGA the LCD displays absolutely nothing, even in normal start up mode.
@@NoelsRetroLab Obviously it's been a long time, but I don't remember any issues with ANYTHING not working in CGA mode. In particular I was very into fractals at the time and I spent a lot of time running Fractint in CGA graphics mode (which yes, was a pretty horrific experience, but it worked!).
For what it's worth this technical reference, which you may already have seen, indicates that it is completely CGA compatible:
www.seasip.info/AmstradXT/ppctech/section1.html#1.11
There are also a bunch of other reviews and resources indicating CGA compatibility. It's actually a very standard hardware CGA implementation, not like the Amstrad PC1520 and 1640 which were indeed pretty eccentric.
The behaviour you showed is exactly what I would expect if the unit was configured for MDA not CGA.
Anyway, I absolutely promise that Fractint in CGA 640x200 mode should definitely work, and if it doesn't there's either a misconfiguration or a hardware fault.
loving these vids,. Totally impressed with your electrical & software skills.... and you're bilingual.... is there anything you're not good at?
He doesn't own a C64. 🤣😂
Really late to the party with this comment, but why is no-one making a Li-Ion battery pack to go into the battery bay for this? Doesn't have to be chargable in situ, basically the innards of a powerbank, sized accordingly and with a 12v output? How many 18650 cell can we get in there? :-)
Bit of blu tack to hold the rear flap in place
We can do better than that! Coming up in part 3 😃
You could try to use some sandpaper to smooth out the surface of those conductive rubber strips from the panel. just make sure you glue the sand paper to a flat and rigid surface, it might work, you got an extra one to experiment with, right?
Yeah, it's worth a try. I have a couple of things I'll try next time based on some of the feedback I got. 👍
omg what you have done? cleaning display contact gum with isopropyl alcohol? gum will expand and contacts will be misplaced, the only repair is wait till it dry and pray if it fits again properly :)
This is the kind of connector that doesn't need to be aligned properly. That's the big advantage of it and why it's used there. As a matter of fact, one of the things I'm going to try is to soak it in warm water to expand it and see if it regains some of the volume and elasticity that it used to have 30 years ago.
Have you forgotten that you have a doner board?
For the zebra strips? No, but they looked the same. I'll try a few things with them next time (before I replace the LCD altogether).
test alternative video out instead of LCD?
Yes, that was working on Part 1. That's how I managed to figure out the computer was actually working.
Dude, you know you don't have to replace the cap with another 100uF 63V right? Anything with approximately the same capacitance, 63V or higher, will be fine. It probably won't even matter if the capacitance is higher, it's only there to buffer the power. They certainly make capacitors that are suitable. You could even pair up two 50uF caps if you liked. You could even get away with lower than 63V, that's just a margin of error cos electronic engineers like to use those where they can.
Trying to replace it with another 30 year old cap from a *broken* brother isn't the brightest idea. Probably lots of caps in both machines are right on the edge of functioning, it's only because electrolytics are usually used as buffers, that circuits can cope with them almost completely failing and still carry on.
I suggest you get some kind of component tester from aliexpress for a few euro. Thats probably better than only measuring the ESR. Just search for GM328.
I do have one of those component testers. You think they're better to check capacitors than the ESR meter?
@@NoelsRetroLab It measures the ESR too, maybe not as accurate as your ESR meter, but I think it's good enough. The good thing is that they measure the capacitance too. If it's not within tolerance it's probably a good idea to replace it. A slightly higher ESR almost never causes any problems in a circuit. But hey, I'm a hobbyist, so my knowlegde is limited.