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UE8, UF8, UG8, definitely start there. Also check UE7 and UG7, if they’re socketed, pull, inspect, re-seat. I had one where UE7 had a bad socket. It produced the same symptoms you describe.

I’ve had TDA7052s fail on me out of the blue. Also, the front up-down volume control buttons can get pressure pinched during reassembly, so they continuously press up, down, or both at once.

I use 3.6v rechargeable CR2032 batteries with a SiliconInsider adapter, works great.

I have a Bolle Presto LC from @joshc, he built it perfectly but unfortunately it has the same issue described above. The PROM is an Atmel programmed by Bolle, so seems unlikely to be the problem. The XC3030 is probably at issue. It’s a legitimate part (TVsat), but doesn’t like being on a...

You can take readings from the molex, yes. Your voltages are all within normal range. IOSB is a TI chip located right above the CPU, U21. The leaky cap that damages it is C45.

PSU seems most likely still, yeah. That said: Every 610 I’ve seen has had some amount of corrosion on IOSB from the adjacent capacitor. The pins and traces on that side should be inspected and solder reflowed where necessary. (Delicate pins so work carefully.) Another possibility is the power...

Very nice score!

Nice find, even with the ABS confetti. At least you can swap much of the case with bits from a Q800. I’ve found that those earlier models often have much better plastics. The whole case comes apart to so many panels and pieces, it’s probably possible to 3D print a good amount of the structural...

If memory serves, yes the light comes on regardless. I also think the volume dial doubles as the on/off switch on these? Been a while since I had one so may be misremembering.

The solder on the SP board’s IC can get so degraded by cap leakage that it turns into resistive metal dust. I had to basically chisel the old stuff off the pins with a dental pick (a tip I picked up from @David Cook I believe), then I cleaned the pads and added fresh solder. Working great now.

Necropost. Found an Interware VDR-2L Nubus card, posting here for posterity. Check out that splash image! It has a selector dial, likely to manage resolutions, but now I’m curious if holding 1-9 on boot has the same effect.

Yeah the 640 x 480 mod just makes for a blurry display in my experience. It’s noticeable enough to me that I tend to eschew it when I build a Mystic, for better or worse. I’d test with an unmodified AB, if you have one, if it’s still blurry you may have a flaw in your display or AB. Caps can...

Thanks for finding that info on the HV card, I missed it on first glance, very helpful! It took some doing, but I have resurrected one of the prototype(?) HV cards, plus two 24-21 cards. Lots of bad solder and bent pins. I haven’t benchmarked them yet, or tested on anything larger than the...

Yes! Glad to hear the card was in good shape, and congrats on the conquest.

Saw one of these in a CC2 recently, the LB looked pretty crusty but I was tempted because I knew what was in the PDS slot. Same auction?

You may have to reflow UB13, UD13, and UE13, Q3, Q4, D5, D6, etc. In some cases the solder is so degraded I have to scrape it off, it becomes like powder and won’t flow anymore. It’s a big problem area as @croissantking mentioned. Check continuity anywhere you see dull and dark solder or...

Tip: pick up a set of “desoldering needles”. They’re hollow metal tubes intended to clear vias, dubious utility in that department. But they are amazing CPU pin straighteners! I have also heard the tip of a mechanical pencil can do the job in a pinch.

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...

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...

That is funny, how odd. That coil filter shouldn’t be polar either, so it’s not for L3. I wonder if this is a silkscreen error. Or does it suggest that a polar cap might work there? That would be convenient.