LisaList2
General Category => LisaList2 => Topic started by: Lisa_in_Paris on December 18, 2023, 08:07:41 am
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Hi all
First thank you for accepting me in this well known Lisa Community.
Last month I bought a Lisa 2/10 and when powered on there is nothing on screen.
The power led stays on, widget is spinning (noisy) and there are 3 beeps when no keyboard is plugged in.
I tried to connect an sternal display and there seems to be some kind of scrambled picture.
The neck of the CRT is glowing.
What should I check now ?
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Twiddle the knobs on the back of the machine, these are the brightness and contrast knobs. If these fail to restore the picture, the analog board has extra knobs you can twiddle that adjust things like picture size and I think tube voltage.
The obvious warnings about CRT voltages being high enough to injure and/or kill you apply. Basically don't lick the thick red wire and you'll be fine.
You won't be able to get a usable image off the Lisa's video out port on 99% of displays out there. There's a few period external CRTs out there that can sync to the Lisa, some professional LCD monitors can, and it's also been discovered the OSSC can sync to the Lisa. That you are getting an image off your Monitor II is a good sign and it looks like you're stuck at a ROM error. Check the LisaFAQ for information on the error beeps: https://lisafaq.sunder.net/lisafaq-hw-rom_beeps.html
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Seconded everything said above.
If you're getting 3 beeps when the keyboard is disconnected (high, high, low?), it points to things mostly functioning except the display.
Start by working with those potentiometers and see if you can get a picture. If not, I'd investigate your video board and see if it needs to be recapped / otherwise repaired.