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You are in the unenviable position of not having a known working set of hardware with which you can trade components one at a time. So your problem could be anything, really, including the PS replacement. There wasn't much in the way of 3rd party upgrades, but Apple made a variety of...

Useful tidbits, but my goal was to make it easy for folks to identify. If you find an Apple PPC604e card set for 250MHz or faster, then it is a Mach V card as they did not make any other PPC604e cards at those speeds. Yes, the processor is actually a 604ev or 604r, but the user isn't going...

There are three versions of the 9500/9600 board and three versions of the 8500/8600 board. Apple may have built more revisions, but there are three that matter to hobbyists. PowerMac 8500, PowerMac 8600, PowerMac 8600 Enhanced (AKA Kansas) PowerMac 9500, PowerMac 9600, PowerMac 9600 Enhanced...

As long as we're on the "7200 is weird" topic, a careful reading of the Hardware Developer Note for the 7200 suggests that it supports up to 256MB DIMMs. I don't think anyone ever made a 256MB FPM DIMM of the necessary type, but in theory, the 7200 could go to 1 GB of RAM, if someone did make...

You might check whether the SOP 40 has the same dimensions as the SOP or PSOP 44, but it shorter. If so, you probably use the same socket and just install it at one end. Here's a datasheet for a chip that uses PSOP 44 so should have dimensions. For that matter you could use two of the chips...

The most common cause of this issue is that the heat sink grease on the CPU has turned to chalk, and needs to be thoroughly cleaned and replaced. I didn't see it mentioned in Josh's list of things he tried, although with all the other board maintenance he did I'd be surprised if he didn't...

Hopefully someone else will stop by to help. My knowledge of the Q840AV is almost purely theoretical, unfortunately. I have a couple of boards from which I've removed the caps and cleaned the boards, but haven't gone any further, like replacing the caps and testing them. They worked when I...

If you two are referring to my post about the problem possibly being a bad inverter, the chip in question is a standard logic chip. Something like an SN74HCT05 or some such. Otherwise, apologies for interjecting. One should also note that most of the rare Apple specific components on the...

That's great news! Good job.

If it's 64 pins, then certainly a position for a ROM SIMM.

@BetaC There was also a long thread about adapters for SCA drives (wide 80 pin drives) and upper byte termination several years ago. Maybe more than one. The end point was that @max1zzz ended up designing and building some adapters. I think they're long since gone. But it might be a...

Both the internal floppy drive and the external floppy drive have an interface board between them and the main board. The internal and external boards have very similar component sets, except the internal board seems to lack the GAL. It is conceivable that Outbound used the floppy...

Are you saying if you just plug the floppy drive in without a disk, the ? never appears? Same for SCSI? If that's the case, I'd check for damage around Grand Central (343S1125). Or in the traces that connect it to Bandit (343S1120). Grand Central is a PCI device. SCSI and floppy...

Sorry for the late reply. I haven't been checking back here in a while. Too busy. I repaired an ANS logic board many years ago, and the problem it had was a bad inverter. Just a logic inverter. It was probably a dual or quad inverter because it was in an SOIC or similar package. Not...

So that's a Kansas, AKA 8600 Enhanced.

I've been thinking about cloning the floppy adapter and a couple of potential issues occurred to me. I'll post them here to preserve them. Again, list of major components is here: https://www.prismnet.com/~trag/Outbound/Adapter%20Parts%20Lists These should be demystified by creating a...

Ah, that's sad, but not catastrophic. I know I have another of each unit. But it slows things down, and the scary progression would be to sequentially kill all my Outbound accessories.... Also possible I killed them desoldering them. Do you know how tolerant they are of heating after...

Here's a fellow having the same problem (not the issue he posted about) but no solution is offered. https://www.eevblog.com/forum/projects/xgecu-tl866ii-plus-programmer-old-devices/

I hope these aren't damaged. Still worried about treatment when I sent them to a fellow many years ago. Anyway, I keep getting this when I try to read one of the chips on the TL866II+. Note that I tried this both with the FLASH and Encrypt chip boxes checked and unchecked. This image...

Wondering about whether Outbound modified the floppy drive... There are a couple of wires near the rear of the floppy drives, which could be bodge wires. However, happily, I found this website with some pictures of another U0DA floppy and the wires are present on it as well. Which...