This seems very similar to a problem a few weeks ago where the contrast signal was absent on the LCD connector. One of the leaking caps had eaten through the contrast control line. A quick check of the continuity between pin 4 on the LCD connector and the base of T23 would confirm that is what has happened (or not).
IIRC the original poster solved their problem so hopefully they can chime in too with any tips. From: M100 <m100-boun...@lists.bitchin100.com<mailto:m100-boun...@lists.bitchin100.com>> on behalf of Stephen Adolph <twospru...@gmail.com<mailto:twospru...@gmail.com>> Reply-To: <m...@bitchin100.com<mailto:m...@bitchin100.com>> Date: Monday, August 19, 2019 at 6:47 PM To: "m...@bitchin100.com<mailto:m...@bitchin100.com>" <m...@bitchin100.com<mailto:m...@bitchin100.com>> Subject: Re: [M100] M100 display not working, all else seems good I would start checking the signals at the LCD connector. Ensure the voltages are present, and that the contrast signal is also there and adjusting well. Sometimes if you hold the screen at different angles you can see faint text. Give that a try. Seems like you m100 is mostly working... On Monday, August 19, 2019, chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net> <chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net>> wrote: Hello, New to the list. Just pulled my Model 100 out of storage where it had been for at least 20 years. It would not power up so I have replaced many of the electrolytic capacitors (several of which were obviously leaking) including all the ones near the power switch (C83, C82, C85, C84, C90, C86, C92) and also four 10uF caps over nearer the modem switches (C49, C50, C54, C55). It will now power up but there is no display. I know it is powering up because I am able to blindly go into Basic and type "beep" and the speaker beeps. This also proves the keyboard is working. I am powering with four fresh AA batteries. I've tried adjusting the contrast knob. I've tested the NiCD battery and it is showing 4.4v. I've tested VDD (+5v), VB (+5v), and VEE (-5V) and all test solidly good. Ribbon cable has been reseated and looks good. When I do a Reset, I can hear a slight click from the speaker so that button is working. I have tried doing a cold reset (control-shift-break-reset) and still no display. When I power off, the battery LED flickers quickly so that is working. What would be my next steps? Is there a good place on the LCD to test to make sure it is getting good power? If so, where? Thanks in advance, Chad
