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Thread: Resurrecting an old 5150

  1. #1

    Default Resurrecting an old 5150

    So I picked up a beat-up looking 5150 from a guy and I've been spending the last week occasionally looking at it and shaking my head.

    It's in rough shape - it's seen water damage - alot of the IC leads have corrosion / rust on them, though the motherboard itself doesn't appear to have suffered any significant water damage. I unhooked the PSU from the motherboard and powered it, just to see what would happen. I was treated to a small pop and slight stink for my trouble. :/

    Anyway, it appears recapping the PSU is the first order of business... but I've never worked with a 5150 before. I'm going to pull the chips and try to clean it down as much as I can, but no doubt a lot of the chips are goners. I came across the technical reference for this machine and I did some quick continuity checks on the power supply connection pins on the motherboard - no obvious shorts - 123 ohms was as low as I saw anything go.

    I don't have a spare mobo to test chips on. At this point, I'm just looking for information on how to methodically test / troubleshoot what's really a hot mess at the moment.

    DSC_0034.jpgDSC_0049.jpgDSC_0047.jpgDSC_0032.jpg

  2. #2
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    Default

    Very... challenging.

    Modem7's site has lots of good information about troubleshooting 5150 machines:
    http://www.minuszerodegrees.net/5150...iag_config.htm
    Basically, you want to at least get some beeps out of the motherboard.

    Although, I'd start with a good disassembly and cleaning. At a glance, you may have some socket issues. Likely some tantalums could go boom so be sure to duck and cover when powering it on. You will probably need to replace the DIN keyboard and cassette plugs. Expect bad RAM chips, and feel very lucky if it is not more than that.

    Hopefully that pop from the power supply was just the RFIA capacitor, you will absolutely want to re-cap it if you want to even try using that power supply. If it were me, I'd probably look for life in the motherboard using a different supply before that to see if it is worth it.

  3. #3

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    Quote Originally Posted by SomeGuy View Post
    Very... challenging.

    Modem7's site has lots of good information about troubleshooting 5150 machines:
    http://www.minuszerodegrees.net/5150...iag_config.htm
    Basically, you want to at least get some beeps out of the motherboard.

    Although, I'd start with a good disassembly and cleaning. At a glance, you may have some socket issues. Likely some tantalums could go boom so be sure to duck and cover when powering it on. You will probably need to replace the DIN keyboard and cassette plugs. Expect bad RAM chips, and feel very lucky if it is not more than that.

    Hopefully that pop from the power supply was just the RFIA capacitor, you will absolutely want to re-cap it if you want to even try using that power supply. If it were me, I'd probably look for life in the motherboard using a different supply before that to see if it is worth it.
    I've really got nothing to work with, so unless it's going to cost me a lot more to recap the PSU than buy one off ebay, I'll have to go that route. I figure I can mod an ATX PSU, though, if I have to - I've seen some info on how to get the -5v output...

    The sockets have a lot of corrosion in them, so I figured wasting a can of DeOxit on this is probably the first order of business. lol I also expect to be doing a recap of the mobo. I really don't expect this to succeed, if only to be realistic. But I'm going after it because I've never had a 5150 and, honestly, I could use the practice and education.

  4. #4
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    Default

    Quote Originally Posted by joelgraff View Post
    I've really got nothing to work with, so unless it's going to cost me a lot more to recap the PSU than buy one off ebay, I'll have to go that route. I figure I can mod an ATX PSU, though, if I have to - I've seen some info on how to get the -5v output...
    What makes you think the PSU needs recapping? Just checking you've diagnosed the fault and not just throwing parts at it.
    As mentioned above, minuszerodegrees has a great load of information including a step by step guide to basic power troubleshooting. For me the most common cause for a PSU to not start on that era of machine is a short on the motherboard.

    TBH I'm yet to need to replace any caps in my IBM PC or PC XT supplies (except the RIFA's and they're not required for operation), and that includes an early model from 1982.

  5. #5

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    Quote Originally Posted by SomeGuy View Post
    Very... challenging.

    Modem7's site has lots of good information about troubleshooting 5150 machines:
    http://www.minuszerodegrees.net/5150...iag_config.htm
    Basically, you want to at least get some beeps out of the motherboard.
    Getting beeps will pose a problem in itself.

    DSC_0038.jpg

  6. #6

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    Quote Originally Posted by SpidersWeb View Post
    What makes you think the PSU needs recapping? Just checking you've diagnosed the fault and not just throwing parts at it.
    As mentioned above, minuszerodegrees has a great load of information including a step by step guide to basic power troubleshooting. For me the most common cause for a PSU to not start on that era of machine is a short on the motherboard.

    TBH I'm yet to need to replace any caps in my IBM PC or PC XT supplies (except the RIFA's and they're not required for operation), and that includes an early model from 1982.
    I really haven't taken anything apart to look at it yet for a lack of time. Eventually I'll get into it and really see what I'm dealing with, but right now I'm just collecting as much information as I can and assuming the worst case until I know better.

    I have heard of a number of people saying they've never needed to recap IBM boards, so that's encouraging to hear. So long as I get constant and correct voltages on the PSU, I don't plan on worrying about it.

  7. #7

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    Quote Originally Posted by joelgraff View Post
    I really haven't taken anything apart to look at it yet for a lack of time. Eventually I'll get into it and really see what I'm dealing with, but right now I'm just collecting as much information as I can and assuming the worst case until I know better.

    I have heard of a number of people saying they've never needed to recap IBM boards, so that's encouraging to hear. So long as I get constant and correct voltages on the PSU, I don't plan on worrying about it.
    Moderators took so long I'd forgotten I gave my first reply to this thread when I gave the third... lol

    ...or maybe I'm just getting old.

  8. #8

    Default

    Quote Originally Posted by joelgraff View Post
    Getting beeps will pose a problem in itself.

    DSC_0038.jpg
    Party hard with PC speaker?
    IBM PC 5150(A): IBM PC 5150(B): IBM PC 5160 (64-256k): IBM PC 5160 (256-640k): IBM PC 5170 (099): IBM PC 5170 (319/339): IBM PC 5140: IBM PC 5162: IBM PC 5155: IBM PC Expansion Unit 5161:
    WANTED!: IBM 5175 monitor, IBM 5145 monitor, IBM PC/XT/AT rear screws, Intel INBOARD 386AT card, IBM 5140 keyboard, very early IBM PC (S/N: under 5000)
    My IBM PC hardware collection

  9. #9

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    Quote Originally Posted by romanon View Post
    Party hard with PC speaker?
    That was the first time I'd seen that, lol.

    What's funny is I looked up the manufacturer - Shogyo. They still make OEM parts. In fact, I looked up the exact same speaker! They won't sell it to me, though unless I buy a lot of 1,000, minimum.

    Somehow I doubt I could resell them. lol

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