Solved N64p - short on the 5V rail

Discussion in 'Nintendo 64' started by Reverand_Cletus, Jun 10, 2019.

  1. Reverand_Cletus .

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    Hello again!

    I seem to have a short on the 5v rail, but can't isolate it. Board looks fine and normal in that area, but every non-ground point in that 5v area around the regulator (and the 5v AV out area & NUC) now connects to ground. 12v into the regulator works, nothing's coming out of it. Removed the regulator, tested a new one, then soldered that new one in, same problem. Not seeing any shorts along the 5v traces, but I don't exactly have a roadmap to work with! :D

    Anyone know of any components - such as the NUC - that, when dead, will short out?

    If I'm explaining this poorly, please let me know! :)
     
  2. Stitches 2 and a Half Dollarydoos Staff Member . .

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    Clear close ups of all areas you soldered to/near pls (basically the whole board)
     
  3. Reverand_Cletus .

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    Here's everything! Recalled after posting this last night that I should share: everything was working fine up to my testing a fan off the regulator (5v .3a fan). Had that running as a stress-test with a heatsink attached for about an hour (and the cooling was aces, fwiw), then the video started locking up. I'd restart the board, and the video would lock up again in less time than before, and so on, until there's no video. Thinking there's a pooch somewhere that was screwed really hard...

    The dp25 is for a working docking solution.

    The cap at C130 and the regulator at U13 were both removed for testing. C130 is functioning normally and was reattached. U13 was replaced with a tested component, as the original was destroyed on initial removal.

    I'm encountering the issue while docked (with full 12v and 3.3v), and while on battery (battery was removed for fault-testing, but is running at 7.4v and 3.3v).

    Thanks in advance for looking this over!

    IMG_20190610_130335.jpg IMG_20190610_130330.jpg IMG_20190610_130249.jpg IMG_20190610_130338.jpg IMG_20190610_130327.jpg IMG_20190610_130318.jpg IMG_20190610_130225.jpg IMG_20190610_130234.jpg IMG_20190610_130309.jpg IMG_20190610_130301.jpg IMG_20190610_130245.jpg
     
    Last edited: Jun 10, 2019
  4. Stitches 2 and a Half Dollarydoos Staff Member . .

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    That's a lot of exposed wire right by the trimmed edge of the board, might be contacting and shorting out?
    exposed.PNG
    Should prolly clean that up a bit. While you're at it, you should also sand the trimmed edge a bit more to remove all that exposed copper peel.
     
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  5. Reverand_Cletus .

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    Thanks! Removed that data line completely for testing, 5v is still shorting out. Guess I'll start moving this work onto another board and semi-start over ¯\_(ツ)_/¯ That would at least offer a clean chance to see if the board is just done, or if something I did pooched it...
     
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  6. Reverand_Cletus .

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    Just a heads up. Removed everything I added to the board. Still shorting on the 5v.
     
  7. Stitches 2 and a Half Dollarydoos Staff Member . .

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    Only other thing I can suggest is perhaps taking some isopropyl alcohol and a toothbrush and cleaning up around anywhere you've soldered to. It probably won't help, but I've fixed a few magic invisible shorts on Wiis that way before.
     
  8. Reverand_Cletus .

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    Good call! Will give that a shot.

    UPDATE: Trimmed the board some and there is no longer a short on the 5v rail. My best guess is I mucked something up with my attempts at preserving video output on the existing pins. Trimmed the power pins, on/of switch area, and the AV pins. Were I going for a standalone portable, this would be great news, however.

    Thank you very much again for the direction!
     
    Last edited: Jun 12, 2019
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  9. Reverand_Cletus .

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    Y'ALL.

    last post on this thread, i swear. Posting in case anyone googles and has the same issue.

    So, both the board I had a problem with and the new one utilize an LED bulb upfront. The original contact broke, so I soldered the bulb directly to a 330 Ohm 0805 SMD just above where the trace broke, off the 3v rail going through there.

    Last night (this morning? Dunno. don't sleep much, so it all goes together), new board worked after I connected the wiring harness I made for the dock. After cleaning it up today - including attaching the bulb to another 0805 thanks to another snapped trace - the board didn't work. After much fiddling, realized it's because of this damn LED hookup. Either I exposed some ground trace and bodged something there, I'm connecting it to the wrong voltage line, throwing off the 3.3v rail, or who knows what.

    THIS WHOLE TIME THE BLOODY THING HASN'T WORKED BECAUSE OF THAT DAMN LIGHT.

    *sigh*

    Will move it to its own line later on. For now, need to make up for lost time.

    Thank you for your time with this!
     
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  10. Stitches 2 and a Half Dollarydoos Staff Member . .

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    lul-png-16-transparent.png
     
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