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There's no harm in testing continuity anywhere on the board, but the suggestion to check around the CPU and the static RAM was basically @mactjaap 's little joke. What @mactjaap did was put your initial post into an AI chatbot, which generated a fairly generic answer that wasn't really based on...

:rolleyes:

Hmm. It does seem like a logic problem. The Lisa has many more ICs besides the 68000 and the static RAM. If you think of it as a numbers game alone, changes are that the problem is with a different chip! So you've got a classic troubleshooting problem on your hands. The usual thing to do is to...

I have a competitor device in a Portable, called the "VideoMacPac". @apm cloned it several years ago. It definitely initialised the CPLD in the way @SuperSVGA describes: you need the control panel to download a binary blob into the device. This card looks very similar, although there's a chance...

This is ridiculous! IBM's repair manuals at least extended the basic courtesy of giving you instructions for how to save your co-worker's life: "Continue without interruption until victim is breathing without help or is certainly dead." --- not a phrase you expect to find in documentation...

Yes, that's my Lisa 0. It's really just cobbled together; I don't have schematics for it. Here's a clearer photo that lets you see the resistor values better: https://photos.app.goo.gl/vDfeNUc8rLhM5PMA9 Get a pinout of the Lisa PSU connector and go to town! (Check on Bitsavers or...

Thanks for this introduction! How are network numbers chosen, and how does a computer joining an existing AppleTalk network learn what the network number is?

The only way to access a disk with a Houdini II card is through BIOS calls. If your OS doesn't use the PC BIOS to talk to the disk (and Linux doesn't), then you can't really run the OS. But if you must have a Unix-like experience, some very old versions of Minix can be configured to access the...

Here's a less risky approach to consider: 1. Take a look at the servo board schematic; maybe find a friend who likes looking at schematics if this is new for you 2. Identify the signal line that carries the coarse servo positioning information from the arm to the servo board 3. Practice using...

I suspect NeoWidEx will not tell us very much at this stage --- the servo is probably not reporting that it's in good health, which means that the controller won't be ready to talk to the Lisa or to NeoWidEx. But it might be worth a try. Here is the haystack where we will need to look for our...

Nuts, well, so much for the simple stuff. Have you got an oscilloscope? I wonder if it would be possible to scope some of the lines on the servo board and narrow down the problem. Having a UsbWidEx would also be extremely helpful here for isolating the issue, but there aren't a lot of those...

As in this video from @ried I think you may be able to find the black piece that the flat flex cable enters and see whether it is moving through the full extent of its travel. Here are some other things to look for: :)

That's a new one to me. I'm not sure why it's doing that. One theory is that the coarse positioning function of the servo isn't working, and it's swinging the arm back and forth against the stops without getting feedback that it's moving at all. Are all the cables and other connectors plugged in...

Thanks @ried , I'm grateful for this thread too. Everything I've learned about Lisa was shared with me for free at some point, so I try to pass it along! Plus I always learn something myself from each case I help out with. In this case, based on the discussion over on LisaList, I've learned that...

I doubt it. While I don't know for sure, there's likely no way to remove the arm from the shaft of that motor without disassembling the drive down to its mechanical elements. If you had the equipment to replace this motor completely (including the glove box or clean room), you would very likely...

I think don't power-cycle the Lisa itself --- just turn the Lisa on and reset it several times via the Reset button on the back. If I'm not mistaken, then each reset will hopefully get the Widget to try to swing the heads again. I'm worried that a lot of powering up and powering down could do...

Hmm... 5+ times isn't the same as a campaign of a bunch of resets and arm movement attempts right after the other, but it's more than nothing at all. I guess if I were you, I'd try one good session of more concentrated activity, and if that's not moving things along, moving on to something else...

But to your point in the message: if a Widget isn't making progress after a few dozen resets like this, I'd assume some other problem or a mechanism so sticky that the patented stepleton resets-n-prayers method ain't gonna cut it :)

Sorry to hear about this @ried , and thanks for trying. The objective is not just to turn the spindle, though, it's to get the arm swinging. The working theory is that gummed up lubrication is making the arm mechanism stiff and hard the move. If you can repeatedly trigger a power-on...

Can third or fourth the recommendation. Needle-nose pliers to tug that pin right out of there :)