When I took it out of mothballs last year I noticed a column of pixels wouldn't turn on so I recently decided to take it apart. I figured I would take the bezel off and the LCD panel would be connected by two electromeric strips. Alas, the Japanese panel manufacture for Clive's laptop had a paper thin ribbon on the end for the rows, glued on top of the panel. That was fine, except, being paper thin, it creased upon opening because there was backing tape to the ribbon to secure it to the LCD, which was stiffer than the ribbon. Once creased you could see that the traces had broken. Just the worst designed LCD panel I have ever seen. I've taken the LCD apart for my other retro computers, a PowerBook 180 and a TRS-80 Pocket Computer, and both were pretty easy to work with.
So I tried to fix it by first cutting away the 1 centimeter creased item. Then I had to figure out how to expose the traces and I played with the cut away item and a swiss army knife; gently scraping along the traces SOMETIMES worked. Since I had so little ribbon to work with, I figured it was pretty much a lost cause. Well, after my first try and accidentally scraping away some traces, the second try I just went with less and got it to work. All back together. I used a pressure fit with some rubbery material to have the bezel press down to make good contact (as I said, they somehow glued it on which took a while to clean off). Oh, and the best part...the dead column of pixels is still their as it must be an issue inside the LCD panel. As Homer Simpson would say...D'oh.
Has anyone else had any experience with the Z88? I'm curious if the screen, made by OPTREX in Japan (model DMF690N), was used by other machines since I'd still like to see if I could find a replacement to fix the bad pixels
https://hackaday.com/2019/03/03/designi ... computers/
Would something similar be possible for the z88?
Really? I figured, other than having an idiot (like me) open it up for no good reason, it's hard to see how they would fail. Are you talking about physical damage from dropping, stepping on, etc...
Well, I did a survey recently. I've had 20 responses so far, and 5 mention possible screen defects. I have 2 Z88, both were bought with screen issues, although I managed to get a new from old stock screen for one - a long time ago.bwinkel67 wrote: ↑Wed Feb 15, 2023 8:45 amReally? I figured, other than having an idiot (like me) open it up for no good reason, it's hard to see how they would fail. Are you talking about physical damage from dropping, stepping on, etc...
According the the EPROM Usergroup mags, the screens can get damaged from being too hot, too cold, or by being exposed to direct sun light for long periods.
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As well as absolute temperature extremes, a relatively large change in temperature within their normal range can also affect them, such as bringing in from a cold area to a much hotter room or the other way round.
They can also develop defects while stored even if not used.
There are numerous failure modes. As all complex displays are multiplexed, failure of any of the control/data or matrix of lines will cause rows or columns to either stay in the “off” (background) colour or stay in the ‘on” (foreground) colour.
I'm guessing that those 3 contacts on the ribbon either had a bit of plastic left (I tried not being too precise scraping it off since I had so little to work with), or it's just slightly misaligned to the contacts on the LCD since scraping also stretched the front end of the ribbon slightly. The electromeric strip for the columns is perfectly aligned, because I had to open things up again after my initial fix, and align it more to the right. When it was misaligned, it caused the M in PipeDream and the D in PrinterEd (both the last letter in the menu window) to have missing pixels in their first column. I can definitely live with that, considering how SOL I felt after having kinked the cable and broken the traces.
It also has a trap door next to the Z80 where the expansion bus lives (anyone every create ayn add-ons?). Finally, the LCD panel is not made by OPTREX, but instead by EPSON (EG2001S-AS-1 8806A3). It's also constructed differently as it has it's panel completely enclosed in plastic with screws on the top.
You can barely see my old panel but that has a metal bezel pinched to the green circuit board. This one has plastic bezel on top and bottom, screwed together (actually a bit lighter). This may not have a ribbon cable to the side since there is less room...though maybe it just folds underneath it (I'm not about to open it up and push my luck). Since I fixed mine, the only reason I'm swapping is because I still have the column of bad pixels, likely due to a flaw in the LCD panel.
However, the screen with the plastic bezel is in bad shape, with weird squiggly lines of dead pixels running through it at the corners.
From reading the EPROM User Group documents, I note that there was a lot of concern about the screen being damaged by direct sun and hot and cold temperatures. I wonder if that's what happened to mine.
However, thanks to you I remembered that I had a spare screen lying around. I removed it in the past because it had a blemish in the middle of the screen. After reading your thread I decided it might still be better than the screen I currently have installed and I switched them.
Here is the crazy thing - the screen no longer has the blemish! It seems to have 'healed'. How is this possible!