Saturn PSU dead, need advice

Discussion in 'Repair, Restoration, Conservation and Preservation' started by Domspun, Mar 26, 2016.

  1. Domspun

    Domspun Spirited Member

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    So the other day, after playing for a few hours, I wanted to change games and it didn't power back on. It smelled like heated plastic. I removed the board, but nothing is burnt. It smelled more around the Ac line area. Could a component overheated and failed? Fuse is fine, switch going to the board works. I suspect something like the parts in the RC1 and C1 locations. How do I test them?

    It's a US first generation model.
     
  2. ASSEMbler

    ASSEMbler Administrator Staff Member

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    Do you have a voltmeter? There's a fuse on there, check it.
     
  3. Bad_Ad84

    Bad_Ad84 The Tick

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    And regarding c1, without looking at a picture of the board it should be a capacitor. It's hardly worth testing them (equipment is expensive) and caps only have a limited life span, if you suspect a cap just replace it and go from there
     
  4. Domspun

    Domspun Spirited Member

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    yes I have, it's fine.
     
  5. sumone

    sumone Spirited Member

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    its likely the voltage regulator rc1. to test, you could measure the voltages but it maybe the quickest to simply replace all caps and also the voltage regulator. replace the regulator with something more modern and the psu will also get less hot in the future.

    and you can also add this fix to improve the psu and avoid further problems:
    [​IMG]
     
  6. Domspun

    Domspun Spirited Member

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    That one is a big gray plastic box.
     
  7. Bad_Ad84

    Bad_Ad84 The Tick

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    Got a good quality picture of the PSU?

    Edit:
    Nm someone posted above that I didn't see.
    Does your PSU match that picture? I read your comment that it's first generation as it's a VA0. But you may have just meant model 1...
     
    Last edited: Mar 26, 2016
  8. Domspun

    Domspun Spirited Member

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    What is it called? is another voltage regulator? So you remove the resistor in the R34 location?

    well, here's mine:
    [​IMG]
     
    Last edited by a moderator: Mar 28, 2016
  9. sumone

    sumone Spirited Member

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    no, you just add a cap with 2200µF 10V at the marked position (green). make sure the polarity is as marked in the pic or you could fry the psu again ;).

    but as said, replace the voltage regulator rc1 and all electrolytic caps. measure line voltages afterwards, and if you get whats needed, it should work again. c1 usually doesnt blows, if theres anything else gone its one of the varistors.
     
    Last edited: Mar 26, 2016
  10. Domspun

    Domspun Spirited Member

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    What's the specifications of this voltage regulator?
     
  11. Bad_Ad84

    Bad_Ad84 The Tick

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    RC1 looks like a bridge rectifier to me. Not a regulator.
     
  12. Domspun

    Domspun Spirited Member

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    Ah yes! Thank you. Do you know the specifications of the part?

    well tested the part as a bridge rectifier and it's fine... Caps are good. The only thing I don't know how to test is the gray box, I tested it as a capacitor and got nothing.

    EUREKA! I think I founded the culprit! It's the varistor in VR1 location. It's the only one that gives me a resistance reading. Gonna change that and see what happens. I will only able to get the part in 2 weeks, I'm going on vacation. At least I know what's wrong.

    BTW, what should I get as a replacement?
     
    Last edited by a moderator: Mar 28, 2016
  13. Druidic teacher

    Druidic teacher Officer at Arms

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  14. Domspun

    Domspun Spirited Member

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    How do I test it?
     
  15. ASSEMbler

    ASSEMbler Administrator Staff Member

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    Someone posted a picture already.

     
  16. Druidic teacher

    Druidic teacher Officer at Arms

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  17. Bad_Ad84

    Bad_Ad84 The Tick

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    First, not his PSU.
    Second, was posted while I was writing my reply and I even edited my post after to account for it.
     
  18. Domspun

    Domspun Spirited Member

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    There's no way to check if it is faulty or not? I do not have any spare parts, I have a JP Saturn, but I don't want to cannibalize parts from it. I'll be on the lookout for a broken Saturn that powers up.
     
  19. Druidic teacher

    Druidic teacher Officer at Arms

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    Last edited: Jun 21, 2017
  20. sumone

    sumone Spirited Member

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    i am sorry for the confusion with my pic post, i just "guessed" by my experience with saturns ;).

    and yes, also mixed up the part from top view, rc1 should be a bridge rectifier then (also a new word for me, "brücken gleichrichter" in german).
     
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