My filthy beige G3 PSU

Discussion in 'PowerPC Macs' started by poiihy, Jan 10, 2015.

  1. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #1
    I took out the PSU of my beige G3 because it was bad and I wanted to salvage the fan. This is what it looks like inside. There are leaked capacitors everywhere! The iPad camera is terrible so the image is not very good.
     

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  2. Intell macrumors P6

    Intell

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    #2
    The white stuff around the base of the components is supposed to be there. It acts like an insulator and stablizer. Don't remove it unless you are replacing the part it is holding.
     
  3. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #3
    Fans

    Here's the fan out of the PSU. Also shown my iBook fan.

    It is quite powerful at full speed (12v). The best speed is at 9v. At 5v it is too weak and at 3v it doesn't work. I powered it by bending and inserting paper clips into the plug and connecting the paper clips to power sources.
    I plan to solder on a 9v battery clip and solder 9v battery clips to some power sources so I can connect this to them, or connect directly to a 9v battery.

    The iBook fan is a 5v fan. It is very loud and whiney at full speed, but runs nicely at 3v. I think the yellow wire is to monitor speed, right?
    The air comes out of the side at an angle, almost sideways, not straight out. I don't know what I can use this fan for.
    I connected it to a USB cable using staples in the plug and the wires wrapped around the staples; this is temporary.
     

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  4. poiihy, Jan 10, 2015
    Last edited: Jan 10, 2015

    poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #4
    No I am pretty sure it is leakage from capacitors. Almost every capacitor in there has this white stuff pouring out of it. It definitely is not in the way that would be used to seal it in place. It looks like leaking.
     

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  5. bunnspecial macrumors 603

    bunnspecial

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    May 3, 2014
    Location:
    Kentucky
    #5
    Every PSU I've opened-Mac or otherwise-has that white crud all over the place.

    Usually the sign of trouble with an electrolytic cap is a "puffy" look on the top, or in really extreme cases the top will actually pop open.

    The blue caps that you're looking at look to me like tantalums, which I don't think usually leak.
     
  6. poiihy thread starter macrumors 68020

    poiihy

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    Aug 22, 2014
    #6
    .
     

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  7. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #7
    What? You mean my PSU is fine?!
    But i've been having trouble with my beige G3 which sound like a bad PSU. Apparently it is not a bad PSU?! My PSU is fine?! :eek:
    Why is there white crap all over the place? It looks a lot like leaking.
     
  8. chibiterasu macrumors 6502

    chibiterasu

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    Apr 5, 2012
    Location:
    London, The United Kingdom
    #8
    I believe the above is correct in this case, the white stuff in this case does look like the stabiliser, I always thought the white stuff was to keep them cooler, in my experience with caps leaking in my original xbox and 2007 dell pc (both the psu built into the xbox and the psu in the dell feature this white stuff), the electrolytic fluid is normally brown and starts to corrode/oxidise either on the cap or the traces on the board.

    You should be able to either see the top bulging with or without electrolytic fluid coming out the top or electrolytic fluid coming down the leg of the cap, or even all of these on one that's really gone.
     
  9. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #9
    So my PSU is fine!!!
    I looked around and none of the capacitors are bulging or exploded. I found this thing with a '+' in it, like a phillips screw; it looks like some adjuster thing for a screwdriver to turn. It is partially covered in some blue, bubbly stuff on the side. Then dust on that. I suppose this is just some glue and normal.

    So if my PSU is fine... then... what else could be wrong with my beige G3? Is it just the wacko nature of the beige G3 that makes it stubborn to boot in certain OS's? I have OS 9 on the hard drive and it wouldn't boot from it. Only once did it start to boot but it got no further than the initial Welcome screen. Never again did it try.
    And it used to get stuck at the happy face when trying to boot into OS X, but now it doesn't recognize anything at all. Just a question mark. This started one time when it tried to boot, it got stuck at the happy face, then randomly restarted and showed the question mark floppy. What could it be? :mad: One 32mb RAM stick died in it so now I cannot boot into OS X anyway (now only 96mb left), but I can boot into the installer. Also the system would randomly freeze. This randomly started when I was using OS X, when it worked. I cannot install a new OS X or anything because it would freeze a few minutes in. WHAT COULD BE WRONG? :mad:


    Well now that the PSU does work, I have to put the fan back. :( I also need to clean the damn thing now, because it does work. When I opened my new 3-pack of gas dusters (aka canned air though not actually air), cause I needed to clean the fan, I found that one gas can had a broken top and was empty! :mad: SO I have to return that and I cannot use those other gas duster cans.
     
  10. bunnspecial macrumors 603

    bunnspecial

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    May 3, 2014
    Location:
    Kentucky
    #10
    It can still be "bad" without having leaky caps.

    Do you have a voltmeter? If you do, you can check the voltage output at the connector.

    Here's the service manual(I think I remember you saying you have the desktop-the tower PSU is a little different) that gives all that relevant information. Also pay attention to jumper J28 as specified in the manual, and make sure it's set correctly.

    http://cdn.preterhuman.net/texts/computing/Apple_Service_PDF/PowerMac_G3/powermac_g3_desktop.pdf

    If you're not getting correct voltages from the PSU, you can use your VOM to try tracing the circuit and look for individual bad components.

    If the voltages check out alright, you can also hook it up to an oscilloscope(if you have one) and see if the output is "clean." You can also watch for spikes, although these can be hard to catch on a scope if they're short and your scope doesn't have a storage function. If the caps are good, though, the scope output will probably look okay.

    Of course, you might also have to concede that your PSU is fine and your logic board is bad. I think that an ATX PSU can be used if you rearrange the connectors, so that might be a decent place to start troublshooting.
     

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  11. poiihy, Jan 10, 2015
    Last edited: Jan 10, 2015

    poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #11

    Yes I think it still might be "bad". I forgot that I also had problems with the ODD. The ODD was acting odd and looked like it was not getting enough power.

    I have a volt meter (analog) but I do not have an oscilliscope of course. :p

    I'll test the voltages at the plugs, but if the power supply is off then wouldn't it not supply any power? I tried connecting green to black but that does not power it on.

    ----------
    Tested it but it doesn't supply anything when it is off. The only power I find is 5v between purple and black.


    ----------
    I put the PSU back in the beige.
    Boots to '?' even though the hard drive has OS 9 which it should be able to boot natively.
     
  12. Intell macrumors P6

    Intell

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    Jan 24, 2010
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    #12
    As above, the white stuff is there by design and does not designate a bad component. If you look, you'll see that it is on some things that are not capacitors.
     
  13. bunnspecial macrumors 603

    bunnspecial

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    #13
    Boot off an OS 9 disk(if you have one) and try reblessing the system folder
     
  14. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #14
    See that's the problem... I don't have an OS 9 disk. Closest thing I have is an iBook OS 9 install which I will try when I get it; it is not here. I tried burning OS 9 disks but they never work. This beige G3 won't boot from burned disks, only official ones.
     
  15. bunnspecial macrumors 603

    bunnspecial

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    #15
    Have you tried cleaning the optical drive? I've never had issues booting either of my beige G3s off burned disks(I make copies of all my OS disks and only use the originals if I have to-the originals are too valuable!).
     
  16. poiihy thread starter macrumors 68020

    poiihy

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    Aug 22, 2014
    #16
    Yes it is clean and I cleaned it and it is still clean. It was from a 466MHz G4 and it worked fine in that. It read burned disks.
     
  17. Ocvist macrumors newbie

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    Jan 11, 2015
    #17
    Correct me if I'm wrong, but I have a feeling that this could be a HDD problem. I wouldn't be surprised after ~15 years of using it.
     
  18. InuNacho macrumors 65816

    InuNacho

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    In that one place
    #18
    Christmas is over, put your spray-on snow away.
     
  19. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #19
    The HDs are fine. It freezes when booted into CD too. And it has not been constantly used for ~15 years; most of the time it has been doing nothing.

    ----------

    ???
     
  20. catzilla macrumors 6502

    catzilla

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    #20
    The CD is from a G4? Did you change any jumpers? The beige uses master/slave, I think most G4s use cable select.
    I have a g3 AIO and MT, I can check settings or jumpers if needed.
     
  21. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #21
    Jumper is set to Master and it always was. The DVD drive works so there is nothing wrong with any jumpers. It's the machine that doesn't want to boot from burned disks.

    ----------

    Oh also
    The fan wire had a PVC tube around it originally. Does it really need this? I put it back without the PVC.
     
  22. Intell macrumors P6

    Intell

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    Jan 24, 2010
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    #22
    If it was on there, it was designed to be on there by someone with an electrical degree and has a purpose for being on there.
     
  23. poiihy thread starter macrumors 68020

    poiihy

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    #23
    What's that purpose?
     
  24. Intell macrumors P6

    Intell

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    #24
    I don't know it, but it was enough to warrant one to be designed into every one of them.
     
  25. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #25
    It's probably just there to be on the safe side, incase the wire flops around and there's a chance that it would arc. In my PSU the wire is far from any other stuff so I think it's fine.
     

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