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I wouldn't say that there is "no doubt". It's always possible that HP made more than one line/revision of PA RISC systems using different pinouts in the 72 pin sockets. That seems unlikely, but back in the day of mini-computers a lot of unlikely things happened...

Beautiful work. There was a thread somewhere in which a fellow basically rebuilt a hole in a board, or a fairly deep gouge, with a UV hardening solder mask. That might have some application in this type of situation. https://www.amazon.com/dp/B01MUB4PJL/?coliid=I1KVVVH33K1WIW I thought I had...

On the bright side, these solvents only cause cancer in California. Other locales, you're safe....

I totally agree with this, except, I might like XP better than 7. It's a tough call. What is this move to do away with clearly labeled menu items and replace everything with squiggles? And how the F(*(& am I supposed to just magically know what the squiggles mean? Yep. And I use Windows...

That does not sound out of line for transistor leakage in such a system. 5V / 16 ohms = ~1/3 amp. I suspect the ones that show 16 ohms are bypass caps which sit directly across GND and the 5V rail and the others are used in a different type of circuit somehow, such as audio. I don't have...

In my experience, the PA-RISC work stations used standard 72 pin SIMMs. At least the ones I worked with did. HP made a pretty penny claiming you needed their special memory in their PA workstations and in their printers of the time.... I once ordered a PaintJet XL300 (IIRC) and it would not...

Fishing weights are cheap and convenient and come in a dizzying assortment of sizes and shapes. However, not good for an environment where toxicity is a concern -- or did they stop making them out if lead? If you have a lot of time, browsing the metals category on Ebay can be useful. I've...

I should have stated it explicitly. I was suggesting electroplating as a method to thicken the connector region of the ROM SIMMs. Make the pins thicker. I don't know if electroplating is a practical way to add enough material to make the required difference.... If I ever find the top of...

Apple used to have a set of User (Human?) Interface Guidlines which they adhered to pretty strictly. The UIGs were based on actual testing and research of what was easiest for folks to learn and use. Or at least the folks they tested it on. I think around the beginning of OSX the UIG's went...

When you program in assembly, you control what your getting. If you're using a higher level language, you're just making suggestions.

I wonder whether one of these copper brush electroplating kits might be a reasonable solution. They also have gold, but the price goes up tenfold... Nickel as well, which should be more durable and for such thin layers the difference in conductivity probably doesn't matter...

The crazy thing is that MacSales (OWC) had hundreds of the 256K modules and was selling them for about $.25 each if you bought a hundred or so. All gone now. I don't know what they did with them. Probably scrapped. I kept thinking about buying a lot, but couldn't think of any use for SRAM...

What resistance are you seeing between the pads? There are normal conductive paths through the MB compents between the GND and Power layers. So you can't expect an open (infinite resistance) between those pads. Typical resistance is actually surprisingly low. But I can't remember if...

That monitor commonly blew its internal fuse for no real reason. If it hasn't already been replaced, you may need to do so.

Maybe one of the old print servers that had a parallel port? Not sure about getting the drivers sorted out though.

I still think converting the HP A2580 RAM module would be the easiest solution although @johnklos 's idea is probably about as simple. Makes me nervous splitting the address space like that, though it shouldn't... I suspect the A2580 is a little cheaper than the HP D4290. The A2580 are...

There was a thread around here (I think*) on filament, available from Amazon, which closely matches the color Apple used. *I know the thread exists; I'm not certain it was on these forums.

Kind of late replying... The voltage regulators are resistance based rather than Buck or Switching type. That means that they basically convert all the excess voltage to heat to get the desired voltage. So it's not surprising they get hot. I've seen similar issues on the PowerMacintosh...

Yes, the desire was for a reliable supply of 32-bit clean ROMs for the SE/30 to enable the various functions that require that. The IIfx and IIsi were the focus because there were actual ROM modules for those two machines in the wild. There were no IIci ROM modules (all soldered to main...

There's a thread around here somewhere all about how to find various connectors. Lists part numbers and sources for things like CPU slots and power connectors. I think Phoenix Enterprises has the ADB port, IIRC. https://www.peconnectors.com/audio-dc-power-mini-din/hws3276/