It ‘could’ also be a driver issue, i.e. the driver for one row is flakey or not being enabled. You would have to try and match the missing row up to the matching driver(s) and check for the proper signals. Looking at the schematic there are several signals marked ‘CS’, i.e. PA0-PA7, PB0-PB1. These are the enable signals for each driver so you could check at the LCD connector to see if they are all being twiddled.
This is a classic issue with the ‘zebra strip’ on the LCD though. You may be able to fix it by releasing the bezel and cleaning the LCD, PCB and elastomer strip well. I did a video on recapping a M100 and made up a color-coded capacitor list with part numbers. There is a link in the video description to download the list. I used a super-cap instead of a new battery on this machine as an experiment. On subsequent M100s I have used NiMh cells though as they have a much longer back up time. Arcadeshopper (another list member) carries the batteries as do I. https://youtu.be/IGTdNMx1V1w Jeff Birt (Hey Birt!) From: M100 <[email protected]> On Behalf Of Kevin Becker Sent: Tuesday, March 3, 2020 8:59 AM To: [email protected] Subject: [M100] LCD Lines I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
