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I have a teac a717 amp which is blowing both 5A fuses.

I have 40v AC at both secondary outputs from transformer and 4 rectifier diodes check out OK. Any suggestions of where to look? It was purchased new in mid 1980's.

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  • pbuckley55 Dec 29, 2008

    To clarify some details, my son had the amp at low volume (yes it was low, I was in the room at the time) but he was feeding the output into his electronic drum amplifier. This was 2 days before Christmas. It made a pop sound through the speakers then there was no sound coming through the speakers. I have replaced one fuse and when I switched it on, the fuse glowed brightly before it blew.

    I will check the output transistors tonight.

  • weirdal May 11, 2010

    The first place I'd look is at the output section (transistors or STK type power packs). Since its from the mid 80s, I'd bet it has the STKs. Look for a big black chip the size of a credit card with about 20 pins attached to a piece of aluminum heatsink. There may be one chip or two.

    Any idea why/when the amp stopped working? Did it just die one day when you turned it on or did it blow out in the middle of a Van Halen album cranked up to 11?


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Thanks for the clarification. From the fuse behavior and feeding the amp into another amp (generally a no-no) it almost certainly is in the output section. If the amp used output transistors (numbered something like Axxxx/Cxxxx where xxxx=0000-9999) there will be some white three-legged low value (.47 ohm or less) resistors that are probably open. FYI the full part numbers for the transistors would be 2SA/2SC so a part marked C3281 would need a 2SC3281. B+D Enterprises (Google them) has most Japanese semiconductors and they have never sold me a fake transistor.

For more repair tips check out www.audiokarma.org

Posted on Dec 29, 2008

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