Recent content by kupouzar

I also noticed that the CPU and several other chips (DSP and VSLIs) get warm. The clock sources also work fine, I checked them with a scope. The voltage of the reset line seems to be around 4.5V at all times.

Hey all, I've managed to get a nice Quadra 840AV. I've cleaned the board with alcohol and recapped it using tantalum caps. It hadn't worked before and has remained the same afterwards. I've found and bodge wired some broken traces between the AMD SCSI/Ethernet controller and the VLSI nearby...

Hey, if the screen is flickering with HDD attached, try measuring the 5V line and adjusting the voltage using the trimmer on the analog board (use a plastic tool). If this doesn't help, I'd try replacing the optocoupler again. There are many kinds and the quality is not always the best. I...

I meant the analog board. Sorry, my fault.

Take a look at this thread. Looks like a low voltage issue. I believe the analog board in the Classic II is similar (if not the exact same) as in the original Classic. Edit: of course I meant the analog board, sorry

So I did it and it works perfectly. As always, thanks for your help!

Okay, so it's indeed a fault of the PSU. And I've also found out that it has previously been tampered with the board unfortunately. Someone cut a resistor off and replaced a diode with a weird combination of two. Tried recapping the PSU but that didn't work out either so my plan is to buy a...

I've just found the pinout. I'll try to short it to the ground when I get back home.

The boards are absolutely pristine, I even inspected them closely and against light. I do own another working 630 though so I'll try a board swap. I don't have it currently at my place though, neither do I have a keyboard so I just tried pressing the push button on the machine. PSU makes a...

Hi all, so I won a very likely new old stock Performa 630 on eBay. I think it is basically new since there's literally no dust inside and the case is still white. There's also no leakage anywhere. However, it doesn't power on. The PSU is most likely working since I even measured very stable 5V...

Good job! Glad that it's finally working ;).

Tbh I'm also starting to run out of ideas. If the other voltages are stable, the fault should be on the 5V rail. Or do they also fluctuate a bit? I don't think that the spilled cap gunk could be that temperature sensitive either. Or maybe there's a fault somewhere else which could lead to...

I believe there is no point in replacing those resistors as they shouldn't really be that heat sensitive. If you apply heat, the resistance increases a little but that is definitely not noticeable if the changes are only in units of degrees. You could try cleaning the AB with an IPA spray. It...

Yes, the whole restoration is very accurately documented there 😆. I didn't have time to read the whole page though. The QP2 is a FET so it should theoretically be more thermally stable but God knows what happens if it's bad. I thought maybe the QP2 was too far away for the freeze spray to reach...

I've also found this. There is some information about the CP21 in Italian and they say that the value is 6.8nF. I also found another Bomarc schematic and there's also 6.8nF. If you look at the bottom of the page, you'll notice that these two schematics are for two different revisions of the...