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Dolch PAC display not working

hagelaars

hagelaars

Member
Joined
Jun 27, 2016
Messages
39
Location
The Netherlands
Two weeks ago I bought a Dolch PAC 62. Everything seemed ok, except the display. When I turned it on, the display was readable, but with interference every few seconds. I thought that it could be the cables from the video card to the display.

There are two cables in between: a 10-pin and a 40-pin ribbon flat cable. Near to the display connection board, the cables come together and can cause malfunction.

So I unmounted the cables, wrapped them with aluminum foil, taped it, and reconnected them. That worked! The display was as clear as never before! After that, I reassembled everything back together and replaced the cables in a good way. With that done, I made a stupid mistake I guess. When everything was reassembled I started the computer, and there was no display reaction anymore. The screen stays black :(

After inspection, I found that one of the cables had some foil coming out at the side of the display connectors. It could be that the foil caused a short circuit… But on the PCB from the displayside everything seems ok. I tried the computer with an external monitor, and it’s just working. So the mainboard and everything is still ok, except something at the display connection board I guess.. I even tried new ribbon cables (10-pins and 40-pins) but the display is not coming up anymore. I don't know what to do right now. I hope that there's somebody who can help me with this issue, cause I'm desperate.

I hope somebody can help. Thank you so much.

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I have a Dolch Pac 64. They're nice little boxes with precisely machines metal frames. I love that industrial design. Too bad they're over priced on the bay.

Let's logically work through what you've done so far as far...

1. Initial power on...fully functional except for a flickering display. Good!
2. Fiddled with cables...display became solid...correlation, causation or luck?
3. Reassembled unit (which with it's tight tolerances would involve more cable fiddling...totally black display.)
- Follow up question...is the display black, yet on, ie...the backlight is still working...or is it black/off/no power?
4. Tested fine with an external monitor...so the video card still works and it doesn't appear damaged, so for now we will presume the internal video connections are still good.
5. Test with new cables. (I don't think there are any twists in those cables, but you can verify that for me). So if you know the new cables have proper continuity, then it's not a cable problem.
6. What's left?

Unfortuantely, probably the LCD itself. 30 years is a long time for an LCD display, so it wouldn't surprise me if the backlight or some other component has failed. I see a number of Dolch Pac 62's on ebay right now being advertised with non-working displays. If you can find someone near you who's proficient in circuit level troubleshooting, you could have him check for a bad component in the power supply section of the LCD unit. Often, a flickering or complete sudden failure of a display is just a power supply component failure. But beyond that, I usually just end up having to replace entire screens.

Sorry I couldn't come up with a solution for you, but I hope this helps you troubleshoot it. Good luck!
 
Hi there to Florida! Thanks so much for your reply!

I like the Dolch PAC also very much and was very happy when I got one! Unfortunately with a broken display by now..
Question you asked at point 3: No, the display stays black. It seems like it's the backlight.. or the complete power to the monitor.?
5: Indeed, it seems no cable problem. I even tried new ones.. that didn't make sense.

Off course it can be that the display fully stopped working after all these years. Do you know if there is a manual/description somewhere with a replacement of a non-general screen (e.g. of another brand or from a laptop/monitor..?).

Anything can help.. thanks!
 
Thanks for your reply.
I already noticed the threads/video's, but it still seems difficult to me.

Thanks again for all the help/suggestions.
 
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