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| Lisa 2/10 black screen |
Posted by: pgreffet on 2023-12-03 23:07:18
Hi all
I powered on my Lisa this weekend and all I have is a black screen. The power lights on, the widget is making a loud noise and there are three bios when no keyboard is plugged in.
The PSU is ref. 699-0190 which is an 1.8 amp configured for european countries.
I have already removed the two big RIFAs inside the PSU but still black screen.
What should I test now ? |
Posted by: bibilit on 2023-12-04 02:38:48
Ptobably not a PSU issue.
Your issue is more on the second board (the one on the picture 0543) or a bad solder joint. |
Posted by: stepleton on 2023-12-04 10:01:42
Is there any sign of life from the display at all ever --- do you see any flickers during power-up or power-down? |
Posted by: pgreffet on 2023-12-04 10:08:15
Is there any sign of life from the display at all ever --- do you see any flickers during power-up or power-down? Absolutely no sign of life from the display. |
Posted by: stepleton on 2023-12-04 14:04:29
Display circuitry is not my specialty; my next move might be to review The Dead Mac Scrolls and extrapolate the syndromes it describes to the Lisa's video apparatus for more inspiratio. Do you see signs of a glowing heater filament in the tube? It's not always visible but you may be able to spot a glow towards the end of the CRT neck. And it nearly goes without saying, but mind the high voltages inside the video system |
Posted by: pgreffet on 2023-12-05 11:11:17
Display circuitry is not my specialty; my next move might be to review The Dead Mac Scrolls and extrapolate the syndromes it describes to the Lisa's video apparatus for more inspiratio. Do you see signs of a glowing heater filament in the tube? It's not always visible but you may be able to spot a glow towards the end of the CRT neck. And it nearly goes without saying, but mind the high voltages inside the video system I will power it on without the upper bezel and see if it glows in the dark. |
Posted by: aplmak on 2023-12-08 01:57:47
I always recap the video board and replace the trimpots on it. |
Posted by: pgreffet on 2023-12-16 09:14:50
The CRT is powered but no picture on it.
I suspect the video ROM to be the culprit. It is written 341-0230-A on it instead of 341-0229. |
Posted by: GRudolf94 on 2023-12-16 09:17:21
What is that suspicion based on?
Back to basic steps: do you have HV? (Can you feel the screen pull the hairs on your arm?) |
Posted by: pgreffet on 2023-12-16 12:41:04
What is that suspicion based on?
Back to basic steps: do you have HV? (Can you feel the screen pull the hairs on your arm?) I think I have HV because of the back of the glowing filament near the CRT neck. I can’t feel the screen pull the hairs on my arm as you say. |
Posted by: GRudolf94 on 2023-12-16 14:46:11
The filament is separate from the HV. Sure, both are generated by the flyback, but one can fail with the other working. See if a piece of paper will stick to the screen when you turn the machine off/on. |
Posted by: pgreffet on 2023-12-17 23:25:34
The filament is separate from the HV. Sure, both are generated by the flyback, but one can fail with the other working. See if a piece of paper will stick to the screen when you turn the machine off/on. Hi
A piece of paper can’t stick to the CRT screen when Lisa is turned on. |
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