Switching mode PSU 5VSB help!

Discussion in 'Technical Repair' started by Demetris74, Jul 22, 2016.

  1. Demetris74

    Thread Starter New Member

    Jul 22, 2016
    Hi all

    I have a rare fujitsu FM Towns Computer and the PSU needed refurbish done that with new capacitors, after that it seems that the 5 volt standby doesn't work, can you please indicate what area and components i should focus and check?
    I have the +12 working, is zero information online or any schematics to help me
    I checked most of the components and measure ok, I might suspect one of the Logic IC's
    Hope you can help me out.

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    Last edited by a moderator: Jul 22, 2016
  2. tcmtech

    Well-Known Member

    Nov 4, 2013
    Did a bad capacitor get installed somewhere on that circuit that is shorting it out?
    Or is one installed backwards?
    Or id there a solder bridge that is shorting that circuit ciruit?

    What is that circuit continuity testing at? Dead short or not?
  3. ian field

    Distinguished Member

    Oct 27, 2012
    A while back I re-capped an ATX PSU - The screen print was wrong under one of the electrolytics, and that vented rather enthusiastically when I powered up.

    Once that was sorted out, it had intermittent STBY 5V - I shoved it on a shelf and repaired an easier one..........................