Sony KDL-40EX500 totally dead, standby power good but still suspect PS. How to check?

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  • ScotttDC
    New Member
    • Oct 2016
    • 2
    • USA

    #1

    Sony KDL-40EX500 totally dead, standby power good but still suspect PS. How to check?

    Hi guys, my Sony TV got fried during an electrical storm. Totally dead: no lights, no nothing. Skipping to the gist: After the storm, zero volts at standby on PS board. I've replaced both the PS board and main board. The replacement PS was supposed to be working, but not guaranteed. The main board is guaranteed to work. TV still dead. Even though the PS now has correct standby power of 3.3v, I suspect that my replacement PS board is the problem. Before I buy another one, I'd like to confirm that.

    Is there a way to test the overall functioning of the PS (beyond standby power) with just a multimeter?

    Longer version: Hi guys, I've been trying to fix my fried TV for several weeks now without success. Based on what I've read on this forum, you guys really know what you're talking about, so I decided to post.

    My electrical skills are basically nil, but I'm a little handy, I have a multimeter, and I figured I could fix the TV. After the TV died, basic research led me to test the big PS fuse and the standby power voltage. Fuse was good, but zero volts at standby. I bought a replacement PS board on eBay that was advertised basically as "as far as I know it works, but can't test or promise anything." Installed that board and got correct 3.3v at standby. But the TV was still dead. Guys on another forum advised me to replace the main board, which I did. That main board is tested (supposedly) and guaranteed to work. But the TV is still dead with that replacement main board.

    Now I think my original main board was probably fine and the replacement PS board I bought is a dud that only works partially. But I want to make sure before I waste another $50+ on another PS board.

    I've searched the forum for threads about similar model Sony TVs and found a couple, but the specific problems seemed different or the discussion went beyond my ability quickly in the threads. The latter also applies to Bud M's TV troubleshooting guide, which I downloaded. I believe I downloaded the right Sony troubleshooting guide, but it doesn't help. The electrical diagrams of the Sony PS boards are basically Greek to me.

    I don't want to desolder and replace components, I just want to order a replacement board.

    - To confirm the PS is the problem, are there test points I can check with a multimeter?

    - Do I need to jump the standby lead to "Power On" before anything else will become testable? If so, do I need a resistor to do that and where can I get the right one?

    Thank you very much for any help. Best wishes,
    Scott

    p.s. This is the PS board: https://www.shopjimmy.com/sony-1-474...1-g2-board.htm
    Last edited by ScotttDC; 10-05-2016, 06:48 PM.

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