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EPC 760 PSU fault

HoutkabouterHoutkabouter Posts: 3
in BSS Archive General Discussion
Hi

One of our 760's PSU have no output.

I've checked the OSC test point and the oscillator is working, but the shut-down pin stays high.

I've also checked the famous big resistor/triac problem and all is OK there.

Does anyone have the schematics for the PSU section?

Regards
Lourens

Comments

  • Dan LynchDan Lynch Posts: 472
    edited December 2010
    That product line was killed off when Harman bought the Soundcraft Group. Nobody currently working for BSS knows anything about the 760 or 780. The most knowledgable person about those amps is George McKechnie. His contact info is attached to at least one of these posts. It may or may not still be valid.

    You also may or may not be able to find his contact info by going to Plaxo.com and searching his name.


    Dan
  • GeorgeMGeorgeM Posts: 12
    Hi, do you still have a problem with this amp?
    Have you checked that the legs of the triac are still attached to the triac body, they sometimes come off.

    George.
    020 8133 1313
  • HoutkabouterHoutkabouter Posts: 3
    It's working again, but I'm not really sure what he issue was. Everything tested OK, but in the end I replaced the four main MOSFETs (IRFP450) of the PSU and diodes surrounding it.

    Thanks for the help guys.
  • GeorgeMGeorgeM Posts: 12
    Just for your information, if you have this kind of problem in future. These device would only ever be a dead short if they go faulty, and the 10amp internal fuse would be blown. Another clue is that if the 10amp fuse in the PSU is blown, there will be no flashing fault LED. I use 14N50 devices in replacement of the 450 as a lot of these devices can have too much on resistance, check to see how hot they get.
    George.
    020 8133 1313
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