Image Map Image Map
Results 1 to 8 of 8

Thread: Ibm 5150 63.5w psu

  1. #1

    Default Ibm 5150 63.5w psu

    I have a 63.5 W PSU I'm trying to troubleshoot and I was wondering if there were resources available for getting started. I've found a pieced-together schematic that seems to fit what I have, so that's a starting point.

    Right now, I see it putting out 8V AC on the floppy power connectors and 3.25 vDC on three pins of one of the motherboard connectors. I know it's not designed to run properly without a load, so I can't really trust those readings, but I'd rather not hook it up to the original equipment in order to test it...

    In any case pointers would be appreciated.

  2. #2
    Join Date
    Mar 2009
    Location
    Dublin, CA USA
    Posts
    2,841
    Blog Entries
    1

    Default

    If it were me I'd just start by swapping out all the capacitors in the thing. There is pretty good chance that the issue is with one of them.

    IBM 5160 - 360k, 1.44Mb Floppies, NEC V20, 8087-3, 45MB MFM Hard Drive, Vega 7 Graphics, IBM 5154 Monitor running MS-DOS 5.00
    IBM PCJr Model 48360 640kb RAM, NEC V20,, jrIDE Side Cart, 360kb Floppy drives running MS-DOS 5.00
    Evergreen Am5x86-133 64Mb Ram, 8gb HDD, SB16 in a modified ATX case running IBM PC-DOS 7.10

  3. #3

    Default

    if it's leaking that much AC I'd start with the biggest cap in there, should be right near the mains input

  4. #4

    Default

    How are you testing ? A digital multimeter ? Reason why I ask because you say 8 V AC. Does you meter differentiate between AC and DC ? You should be on DC setting.

  5. #5

    Default

    It almost sounds like it would read correctly if you were to put a load on it.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  6. #6

    Default

    Quote Originally Posted by Stone View Post
    It almost sounds like it would read correctly if you were to put a load on it.

    Well, I gave it a shot. I've stripped the motherboard of every socketed IC, and plugged in the connectors... and hooked up a floppy disk. From what I read, either one should be enough to load the PSU to get it to turn on.

    The result - a popped cpactior on the motherboard and on the floppy disk drive card.

    So I unhooked it and tested the harnesses again.

    I saw voltages briefly before the powersupply (presumably) shut itself down due to no load detected. On P8, I saw it hit +5 and -5v on the appropriate pins. On P9, The +12 hit 9-ish volts, the -12 hit -6ish volts.

    Sooo.. maybe it's ok. But I doubt it. All the same, a recapping may be all this needs after all.

    Just wish there was a way to test it with enough load to feel confident about what it's doing.

  7. #7

    Default

    Buy a 10W 4.7 ohm resistor, and use that as a 5V load?

  8. #8

    Default

    Almost any old hard drive will work as a load.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •