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I haven't done any work on this project in the last few weeks. For a while I was waiting for heat sinks to chase hte reliability problems and more recently, I'm obsessing over my 2021 taxes to get everything where it needs to be.

I don't know if the 7222 will work with a ZIP drive becasue I don't know if the ZIP drive presents itself as a SCSI storage device (hard drive) or as an ATAPI device. Without a firmware hack-date the 7222 will only support optical/ATAPI devices. After you hack/update the firmware, it will...

Could be that capacitor goo damaged/shorted the A12 line to the RAM slots. That address line wouldn't be used on 4MB and smaller SIMMs but is needed on 16MB.

It was good stuff. I couldn't remember that Bank A needs to be populated. But we just don't know what level of detail folks asking for help need, so when there's time, I try to provide excessive detail. :)

To expand on what LaPorta wrote, while you can't test with 7 out of 8 SIMMs installed, you can test with 4 SIMMs installed. So start by removing the RAM in Bank B and test. If it works, then the bad stick is one of the oens you removed. If it fails, then it's one of the sticks still in the...

It shouldn't matter which end is plugged in, it's providing a connection of a certain resistance between the bus signals and a fixed voltage at that point in the bus.

If I remember correctly, I had an ATA DVD-ROM drive connected to a VST Ultra-66 card years ago. I currently have a DVD-RW drive connected to an Acard 6820M, which pretty much guarantees it would work fine with a 6880M as well. The only difference between the two is that the 6880M has on-board...

Which machine does the ROM go with? A number of ROM modules have already been designed, so the work may already be done.

@cy384 Interesting that your photos show that your board still has a 88916DW55 installed. Do you think it would help to step up to a DW70 or DW80? I'm actually kind of hoping that the dW55 works just as well as the other two faster rated parts. Somewhere along the way I ended up with a reel...

Yes, the markings look shady. But I keep checking his feedback for complaints and haven't seen any regarding the 68040s. May just be that no one has been alert enough and angry enough to bother, though. And I've dealt with some sellers who predicate refunds on removing/avoiding negative...

I've been thinking about trying this seller, miantaxia-0. Has anyone tried this one? https://www.ebay.com/itm/323076959423

Signing up for the mutual memory support society...

@weedeewee Looking forward to your results. I'm using 7726 firmware 1.73Q in my tests, mainly. Sometimes 1.69Q. On both Rev. 1.5 and 1.8 I see SCSI ID 8 stuck after conversion. I test all board with an optical drive before conversion, and SCSI IDs were proper -- as the jumper settings...

Good point. That's what I used to do when soldering header strips to the pins of the 68000 for old upgrade installations on the pre-plus machines. Put the header strips in a 64 pin DIP socket before starting. I completely forgot that bit of art. When I get there, I'm still going to try to...

I posted a link for the AT style connectors and pins, somewhere.... It's easier to reuse the connectors from the old supply, but if someone wants fresh connectors, they're available. I just don't remember where I posted those links.... Edited: Ah, here is is...

@Fizzbinn Thank you. I hope that means that 20ns will work. I'm not in much danger of getting to this project soon, too many other immediate things going right now. But I have some of the TAG SRAMs on hand. And I have a bunch of 20ns 32KB X 8 SRAMs. IIRC, the JEDEC pinout for the 32KB...

That's good news. Are you two finding that after putting the 7726 firmware on the 7222, that the ID8 is stuck on the resulting board? That is, all SCSI addresses are 8 + settings. And if no SCSI ID jumpers are installed the boards are showing as ID8.

Interesting to note that in one of the photos that gpbonneau provided the data cache chips are 15ns and in the other photo of the other board they are 20ns. I hope that means that 20ns is fine, and they just used faster on some boards -- as opposed to 15ns is really needed and they found some...

BTW, the Hardware Developer Note for the WGS9150 says that it shipped with either a 512KB or a 1 MB cache, IIRC. It also says that the logic to support the cache is in the HMC (the memory controller chip) and the 6100/7100/8100/9150 all used the exact same chipset, except that the 9150 used the...

Welcome, weedeewee. Thank you for the suggestion and all the other interesting information. I actually just wrote a little PERL script some time ago to input the BIOS/Firmware file one byte at a time and output a new file interleaved with 'FF'. Worked great, but there are many ways to...