Recent content by stepleton

Reversing the screen modification also requires replacing the video state PROM, which is a fast non-eraseable part that (as far as I know) can't be replaced with an EPROM. You can find rectangular pixel compatible video state PROMs from retailers like VintageMicros. It may be worth considering...

Interesting. It might be time now to see what we can see with troubleshooting tools like NeoWidEx. I wonder if it will boot in your Lisa. Given the somewhat squashed appearance of the text in the screenshot you shared, it may be that you have the square pixel modification fitted in your...

Sorry, I meant the Widget behaviour: no sign of it changing over successive power-ups?

That image is a new one on me. Is this behaviour truly consistent --- the same thing every single time?

Hello and congratulations on your lucky purchase. For the widget in Lisa #2: sometimes Widgets that haven't been turned on for a while need some exercise to start working again. Try turning your Lisa on and listening closely to how far the Widget gets in its startup sequence. Once it stops...

This is interesting; it would appear to implicate the complicated logic that your memory board uses to establish its location in physical address space. For more details, see the discussion on PDF page 148 here. Consider also using service mode to inspect the memory locations where the Lisa...

Congratulations!

I would sooner suspect bad solder joints on your motherboard connectors.

PS: Reseating socketed chips can't hurt, generally, provided you do it with the usual care. Worth a shot!

Forgive this post for being quite similar to the one on the other active Lisa troubleshooting thread, but: you now find yourself at the beginning of a classic troubleshooting journey, for which the typical strategies for machines of the Lisa's era apply. Unlike the other poster, you do not have...

Forgive this post for being quite similar to the one on the other active Lisa troubleshooting thread, but: you now find yourself at the beginning of a classic troubleshooting journey, for which the typical strategies for machines of the Lisa's era apply. Unlike the other poster, you will have...

It took me a while to know what you were referring to, as I would ordinarily call this a "panel interlock switch" or similar. But "kill switch" is accurate. Anyway, if you wish to defeat the interlock by any of the means you've suggested, they will all work exactly as you intend. Safety is the...

Worth saying that Adrian Black (of Adrian's Digital Basement on YouTube) attacks an issue like this one on episode 8 of his nine-part repair series: My Lisas exhibit it too, to some degree, and it's easy to find other people online who describe having the same problem. I've just learned to...

Lisa video has a horizontal frequency of 22 or so KHz; it's very odd and few monitors sync to it natively. Most people who use the composite jack use something like an RGBtoHDMI to see the video. I've heard of people using a differently-configured RGBtoHDMI to interpret the separated signals...

It depends: even though the garbage isn't much to look at, it's still informative. The screen image is still a raster, so if you see it, that means the video state ROM and other video gubbins are working at least, and that ain't nothing! Here's where you really do want to hear from folks like...