Yamaha P-250 Speakers not working

I have a Yamaha P-250 where the speakers quit working. I’m running sound out of the line out to computer speakers cringe now and I need to figure out how to repair it. I already replaced a big transistor years ago which fixed it for a few weeks before clunking out again. I’m probably pretty bad at soldering, but I’m ready to try again. My problem is I can’t remember the part # I replaced last time and it stands to reason that that might not be my problem, but a symptom of it. Anyone else have an idea as to where to start, again?

Thanks in advance,


OK - question:
When you turn power on can you hear a relay click after about a second or two ?
If not - then there can be various issues:

  • Blown transistor that turns the relay on-off (if you replaced it before and problem is same - the the diode across the relay may faulty - that diode protects the stored charge in the relay for hitting back at the transistor causing it to fail)

  • List one or both outputs of the STK-401 are having to much DC on the output or completely shorted.

  • You have a power supply issue

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Thanks, I start plugging away at those and reply back after I’ve gone through them.