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Recent content by kupouzar

  1. kupouzar

    Classic II constantly reboots/chimes

    I meant the analog board. Sorry, my fault.
  2. kupouzar

    Classic II constantly reboots/chimes

    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
  3. kupouzar

    Performa 630 won't power on

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

    Performa 630 won't power on

    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...
  5. kupouzar

    Performa 630 won't power on

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

    Performa 630 won't power on

    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...
  7. kupouzar

    Performa 630 won't power on

    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...
  8. kupouzar

    Recapped Macintosh Classic with checkered screen

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

    Recapped Macintosh Classic with checkered screen

    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...
  10. kupouzar

    Recapped Macintosh Classic with checkered screen

    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...
  11. kupouzar

    Recapped Macintosh Classic with checkered screen

    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...
  12. kupouzar

    Recapped Macintosh Classic with checkered screen

    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...
  13. kupouzar

    Recapped Macintosh Classic with checkered screen

    Very strange... Yes, it could be this capacitor, ceramic capacitors also tend to be heat sensitive. According to the schematic it should be a 0.0018uF (1.8nF) ceramic capacitor. I can't really see anything else that could cause this issue tbh... Btw, have you tried tuning the PP1 after the...
  14. kupouzar

    Recapped Macintosh Classic with checkered screen

    That actually makes sense. The LM431 is a shunt regulator which regulates its output voltage by diverting some of the incoming current to the ground. It is basically a Zener diode with some extra circuitry. It also seems that it is supposed to regulate the current flowing down from the LED in...
  15. kupouzar

    Recapped Macintosh Classic with checkered screen

    It might be worth checking all of the components on the line leading to the CNY17, especially the pin 2. Maybe there’s something wrong with the amplifier consisting of QP3 and QP5.
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