Acoustic B200 with No Sound

Discussion in 'Amps and Cabs [BG]' started by Mason Morton, Oct 4, 2021.

  1. Mason Morton

    Mason Morton

    Oct 4, 2021
    From the research I've done, it seems most likely to be the STK404 that's the problem and it's the component that most commonly fails. I want to run this by some of you and see if anyone has any other ideas before I try replacing it.

    The problem started with the amp taking a couple of minutes to "warm up" before sound would come through. After a couple of weeks, it stopped playing sound altogether. The preamp doesn't seem to be the culprit. The clip LED lights if I turn the gain up and play a note. The XLR direct out also transmits the signal. Neither the internal speaker or an external speaker works, so it seems to be a problem within the power amp.

    My hesitation comes from this: I tried testing the STK404 with a multimeter as stated in other posts. It says there will be a short (continuity) between pins 11 & 12 and 10 & 13 if the STK404 is dead. I did not get that short. It measured high resistance as it should.

    I also tested all of the large capacitors with the multimeter and none seem defective.

    Is there anything else I should test or look at before jumping into replacing the STK404?
  2. seamonkey


    Aug 6, 2004
    Mason Morton likes this.
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