Daystar Powercache P33 troubles

[chiptripper]

I have a dead 50mhz P33 Powercache. It neither powers nor caches.

No obvious damage or corrosion. Tried swapping CPU, FPU, oscillator. Checked all the caps and resistors. I just get a bright, blank screen in an otherwise healthy IIci.

At this point, I wonder if a previous owner plugged it directly into an SE/30 PDS slot. Just a theory. If so, looks like 40a, 40b and 40c would’ve seen 12v or -12v. 40a is GND 40c runs to a 74F573D. Anyone dealt with that scenario with a P33 before?

 

[chiptripper]

I ordered a replacement 74F573D (cost about $1), pulled and replaced. No change.

I’m definitely curious if a SE/30 PDS installation would cause damage beyond the latch chip. But again, it’s really just a hunch. Could be something else unrelated.

So, where to look next? P33 is a challenge to probe. Guess I’ll make an extension cable for the PSU and run the LB outside of the case.

 

[JC8080]

You can use an ATX extension cable, there are just some unused pins that hang off the end of the connector.