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Thread: Need help w/ PSU for a Compaq SystemPro XL

  1. #11

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    Quote Originally Posted by Shadow Lord View Post
    If anyone has a recommendation for a good service that is free and handles bigger sizes (ideally without needing an account) please let me know! TIA!
    IMGUR is free and the account takes less than a minute.

    Try IMGBB for no account.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  2. #12

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    Quote Originally Posted by Stone View Post
    IMGUR is free and the account takes less than a minute.

    Try IMGBB for no account.
    Stone,

    These are actually are hosted on imgbb. I may have to make an imgur account for future use...
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  3. #13

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    Sorry...

    Maybe try IMGBOX for another no account possibility.

    I have put lots of stuff on IMGUR, I like it, and it comes highly recommended by many others. I think you can go without an account but it's much more efficient and useful with the account.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  4. #14

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    Quote Originally Posted by Stone View Post
    Sorry...

    Maybe try IMGBOX for another no account possibility.
    My issue with the account thing is that you get marries to the service and they change their terms on you (Photobucket I am looking at you...) If there is no accounts then they are just a disposable resource.... But I don't want to stray away from the meat of this thread which is to get a SystemPro back up and running
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  5. #15

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    What if your ISP 'changes their terms on you'?

    Don't be paranoid... just make an account and reap the benefits while they are available. If worse comes to worse you can always take care of it then.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  6. #16
    Join Date
    Apr 2015
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    Quote Originally Posted by Shadow Lord View Post
    Bear,

    That was my initial thinking as well. However, all the caps look pretty good. The PSU is actually in very good VISUAL shape for its age. I will post pictures later today. I have access to an ESR meter so I can ceck the smaller capacitors.
    Visual inspection isn't going to tell you anything about old capacitors. I see capacitors all the time that look fine, but are as bad as you can get. Shorted, off the charts ESR, excessive electrical leakage, etc.

    All capacitors should be tested on an ESR meter and also observed for leakage. If you see capacitance readings that are more than 20% out of tolerance in either direction, they're bad. The fat line filter caps also need to be checked, they can go bad and cause all sorts of havoc.

  7. #17

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    It'll be a capacitor outside the power supply, and you can't tell by looking. You don't need an ESR meter, the offending part will be a dead short ...if that's the problem.

  8. #18

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    Quote Originally Posted by bear View Post
    It'll be a capacitor outside the power supply, and you can't tell by looking. You don't need an ESR meter, the offending part will be a dead short ...if that's the problem.
    Well, I finally had a chance to come back to this project. I checked all the capacitors with an ESR meter and nothing looked "off the charts". Also there was no dead shorts. There was one bad looking capacitor but it tested fine with the ESR meter.


    I also went through checking all the diodes and everything looked fine except for two: in both cases the diode (in circuit) reads zero in both directions and shows as a short when tested for continuity (again in both direction). At first I thought I had found the problem but I have two other (obviously non-working) SytemPro XL PSUs and on the other two the diodes behave the same. I can't bring myself to believe that two diodes in the same place on three different boards all died and are causing the problem. However, I also don't know enough about PSUs to know if there would be a circuit design that would create this kind of behavior.
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  9. #19

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    Quote Originally Posted by Shadow Lord View Post
    I can't bring myself to believe that two diodes in the same place on three different boards all died and are causing the problem.
    It might be a design thing: Part choice and location.

    If you want a device to barely pass warranty, just design some marginal electrolytic capacitors close to hot areas.

  10. #20

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    And this is probably why I should not be doing this in the first place...

    20191010_011128 (Medium).jpg

    Surprisingly the trace is still in tact and there is continuity. The Diode seems to be okay to.... My multimeter probe... Well it ain't as sharp as it used to be...
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

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