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Thread: Repair of 5160 XT power supply

  1. #21

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    Quote Originally Posted by modem7 View Post
    5160 motherboard receives +5V.
    By receive you mean that one of the pins 2,4,5 or 6 supplies 5V?

  2. #22

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    It just exploded - the C56 capacitor on the motherboard.

    https://1drv.ms/f/s!AsoOXKPKfQ6FgoAVmp8klqoue7CJyQ

    And in the final moment I forgot to put my protective glasses ... and watched flares go around me. Quite a show it was ... next time I will record

    So I tested the power supply, the original one ... with glasses and with some distance. It worked. It did not require any load though. Mine is SCHRACK EGO ...
    So this motivated me to finally test the motherboard ... while the kids are not at home ...

    My eyes are OK

  3. #23
    Join Date
    May 2006
    Location
    Melbourne, Australia
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    7,008

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    Tantalum capacitors, like C56, normally explode open circuit. C56 is not required for 5160 motherboard operation (it only filters the +12V passing through to the expansion slots). You may discover that your 5160 is now working. Is it ?

  4. #24

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    Quote Originally Posted by modem7 View Post
    Tantalum capacitors, like C56, normally explode open circuit. C56 is not required for 5160 motherboard operation (it only filters the +12V passing through to the expansion slots). You may discover that your 5160 is now working. Is it ?
    I removed it completely with cutters and I get some beeps. The thing is that I do not have a monitor to see the exact post error. I will put new capacitors and try to find a compatible monitor or VGA card.

  5. #25

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    OK, I got both the power supply and mother board working.
    I have put an OTI VGA card, changed jumpers to ON for 5 and 6 and it worked. I was shocked . The memory extension card worked up to 640 KB (unbelievable).
    So I got to see the POST errors: 601. It does want floppy drive, but unfortunately both my floppy and hard disk do not seem to work.
    It says press F1 to continue ... but I do not have a compatible keyboard...

    Thanks everyone for the help!!!

    XT-IDE seems partially recognized - it detects the external ROM even if I do not yet see the XT IDE boot menu.

  6. #26
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    7,008

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    Quote Originally Posted by tonata View Post
    It just exploded - the C56 capacitor on the motherboard.
    Quote Originally Posted by tonata View Post
    I removed it completely with cutters and I get some beeps.
    I have added the failure of C56 to the list at [here].

  7. #27
    Join Date
    Sep 2020
    Location
    Stuttgart, Germany
    Posts
    1

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    Hello everybody,

    I'm new to the forum. My name is Chris and in my spare time I repair and restore old PCs.

    But with my current project I need your help. I have an IBM PC XT 5160 that I want to fix. Right now I'm sitting in front of the power supply and can't get any further with a few components.

    It's about the power supply: IBM-1501438 130W 220 VAC

    and the following components:

    1. 329 1086-1 (Motorola). The name Q1 is on the circuit board.
    2. 329 1086-1 (Motorola). The name Q2 is on the circuit board.
    3. MC7905CT QQ831517 (Motorola) The name IC3 is on the circuit board.
    4. 371-03 83 37 (Motorola) The label CR1 is on the circuit board.
    5. 371-03 83 37 (Motorola) The label CR2 is on the circuit board.
    6. 356-01 83 38 (Motorola) The label CR5 is on the circuit board.


    The capacitors were replaced with new ones. I also replaced the Rifas.

    Some of the transistors or what the components are called seem to no longer work properly. There is no voltage on the +5, -5, +12, -12 rail.

    I uploaded photos of the components.

    I hope you can tell me what the names of the components are nowadays so that I can buy them.

    greetings

    Chris









  8. #28

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    Quote Originally Posted by ChriRoBa View Post
    Hello everybody,

    I'm new to the forum. My name is Chris and in my spare time I repair and restore old PCs.
    Welcome
    But with my current project I need your help. I have an IBM PC XT 5160 that I want to fix. Right now I'm sitting in front of the power supply and can't get any further with a few components.

    It's about the power supply: IBM-1501438 130W 220 VAC
    IBM had contracts with various PSU manufactures who supplied IBM with PSU's, Not to mention all the "Clones" out there, Who is the manufacture of your PSU ?
    and the following components:

    1. 329 1086-1 (Motorola). The name Q1 is on the circuit board.
    2. 329 1086-1 (Motorola). The name Q2 is on the circuit board.
    3. MC7905CT QQ831517 (Motorola) The name IC3 is on the circuit board.
    4. 371-03 83 37 (Motorola) The label CR1 is on the circuit board.
    5. 371-03 83 37 (Motorola) The label CR2 is on the circuit board.
    6. 356-01 83 38 (Motorola) The label CR5 is on the circuit board.


    The capacitors were replaced with new ones. I also replaced the Rifas.

    Some of the transistors or what the components are called seem to no longer work properly. There is no voltage on the +5, -5, +12, -12 rail.

    I uploaded photos of the components.

    I hope you can tell me what the names of the components are nowadays so that I can buy them.
    Unfortunately these old PSU's can have components that have long gone obsolete and can be hard to find replacements, How do you know those parts in the photo's are faulty, Have you tested them ?, What happened originally was the fuse blown ?, It sounds like you are replacing components and hoping for the best, Sometimes it works and sometimes it don't and wastes money, .... My thought's on the parts in photo's are...

    1 and 2 = High speed switching transistors
    3 = Negative voltage regulator, It outputs -5v
    4 and 5 and 6 = Rectifiers

    Just my thoughts, I could be wrong, I would suggest you familiarize yourself with SMPS and always bear in mind the dangers of working with PSU's, There are lots of websites around on SMPS repair etc, If you can't find data sheets, maybe look for old motorola data books though they may or may not help.

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