Lisa 2/10 black screen

[pgreffet]

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 ?

 

[bibilit]

Ptobably not a PSU issue.

Your issue is more on the second board (the one on the picture 0543) or a bad solder joint.

 

[stepleton]

Is there any sign of life from the display at all ever --- do you see any flickers during power-up or power-down?

 

[pgreffet]

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.

 

[stepleton]

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

 

[pgreffet]

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.

 

[aplmak]

I always recap the video board and replace the trimpots on it.

 

[pgreffet]

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.

 

[GRudolf94]

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?)

 

[pgreffet]

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.

 

[GRudolf94]

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.

 

[pgreffet]

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.