Any ideas on how to fix this? When I put this card in my IIci I get the normal chime followed by a funky chime.
iirc the SE/30 was based off of the iix, so it should be closeCheck for any obvious bad/ugly contacts on the connector and back of board first. If you're lucky it might be something simple. What is the history of the accelerator? Has it worked before?
If the simple stuff fails.... you're going to be getting into some fairly esoteric troubleshooting. Assuming the SE/30 design is a close relative of the IIci design (it definitely appears to be), I mainly experienced those weird slow chimes in my experience when there were clock issues. Such as a too slow or weak clock on the accelerator. If you have a quality multi-meter, measuring the average voltage of the top right pin of the crystal may give some useful info. Expect 2v or higher would be expected, 2.5v is ideal, and anything higher probably means the measurement is no good.
If you have a spare 30-50mhz crystal osc (anything in that range should work) you could swap out the one on there for troubleshooting purposes. Or even bodge something up, I used a RP2040 dev board as an adjustable clock generator for my experiments.
There are no caps that are critical to functionality, and if the buffers were bad it is improbable that it would come up enough to even make a death chime. Likewise the SRAM and TAG SRAM are not required to boot, so problem is unlikely to lie there.
Do you have any advanced troubleshooting tools such as a logic analyzer or an o-scope?
Sorry, good point: all of my post is in the context of the accelerator design, not the mac, though you are right about the similarity. I built a clone of the Diimo for SE/30, and I see functional analogs to the IIci board design where I'd expect to see them so I'm using that as a basis for troubleshooting.iirc the SE/30 was based off of the iix, so it should be close
Data SRAM and Tag SRAM is not required for the accelerator to boot (without the cache enabled via control panel). Unless things are bad to the point where the chip OE is not functioning as expected on data SRAM (ie. holding the accelerator's local data bus high/low), anyways.I think you already have done some of these but I'd start by...
Deoxit the main connector, plus CPU and FPU sockets
Clean the board with ipa
Inspect the reverse side looking for scratches that cut traces or bad solder joints
Check for shorts across any capacitors Replace any electrolytics. Can't see any caps so guessing they're on the reverse? Or under chips?
Check the clock is running with a fast scope, freq counter or multimeter as above
Test it with a different CPU and FPU (simply because they're socketted)
If I was really stuck, I'd try desoldering the cache and tag RAM to see if it worked without, because that can fail... After that I'd worry it was a failed logic chip - do any get warmer than the rest?
Are all the logic chips soldered?
Leaking isn't the only way caps fail. Ceramic caps like that can fail short, thats why I was saying check them with a meter.Yeah no real caps to speak of that can leak. Here’s a picture of the back.
View attachment 60717
I was actually going to try a different PSU and actually I was going to try it in my Mac II as well with the adapter just to see. I read somewhere where bolle mentioned something about having trouble with a diimo card of some kind in his IIci that worked in his Mac II.