Have you checked the on board voltages? It sounds like the –5V is not working. I had a similar issue with my 8201A the two main caps that sit on the –5V rail were bad. It is quite a common problem.
I did end up replacing all the electrolytics in the end, just to save having to dismantle it again. After you replaced the internal battery did you try a cold reboot to clean out the RAM? It could also be that the +5V is having problems. From: M100 <[email protected]<mailto:[email protected]>> on behalf of Jason Benson <[email protected]<mailto:[email protected]>> Reply-To: <[email protected]<mailto:[email protected]>> Date: Monday, May 28, 2018 at 8:59 AM To: <[email protected]<mailto:[email protected]>> Subject: [M100] PC-8201A Blues Hey guys. I got a NEC PC-8201A awhile back and I've had some trouble with it. When I first got it, it to worked fine for a few minutes then the screen blanked and it wouldn't respond. I tried a number of things including replacing the internal battery but nothing seemed to work. Later I heard of someone having trouble with a board because the flux from their solder was shorting connections so I decided to open the 8201 and clean up my work on the battery. It started working again!! I spent about a half hour tinkering with it when the contrast started to fluctuate, then the screen faded out all together and now it won't display anything. Any ideas? P.S. when the screen died I was trying to figure out why it wouldn't switch between memory banks even though it had a full set of ram upgrade chips, but that's secondary to the screen issue. -Jason
