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power amp board

  1. D

    Power supply help for qx-747

    Working on a pioneer quad for about ever now. Recapped and replaced transistors on the power supply board. Did not replace any resistors or diodes. Attached a pic of readings I’m getting compared to spec. Of by almost exactly half at pin 23, by 30% at pin 17. I don’t understand yet how to...
    • Dkat69
    • Thread
    • advice needed power amp board repair advice help needed repair help
    • Replies: 5
    • Forum: DIY
  2. richardg0n

    Why Does the 2325 Power Supply Relay Function Only When Amp-Free

    Greeting AK, Looking for troubleshooting advice. Restoring another 2325, and after recapping PS, the relay on PS will not open/click when the amps are connected(powered and RCA connected). PS, amps, Pre, and PU01 have been recapped(see pics). Here is the sequence of steps I have taken to...
  3. jpreza

    Pioneer SX-750 Power Amp - Need Help

    Good day everyone, Currently troubleshooting an issue on a Pioneer SX-750 Power Amp board. Recapped it and replaced the following transistors: Q3, Q4, Q5, Q6, Q7, and Q8. Left the original 2SA798s (Q1 and Q2) alone as they tested good. After making sure that everything was plugged in...
  4. bzenic

    Pioneer SX-650, Zero Voltage at Power Amp pin 31

    The FM and AUX / mic inputs work. On the flip side somebody was messing with bulbs and the connecting wires, power light also doesn't work. According to the service manual on the power amp board I should get the following measurements: 30 V at pin 30, , 7.5 V at pin 31 (this is used to feed...
  5. H

    Pin out voltages on SX-1050 PA board output transistors

    This is rather embarrassing. I have rebuilt around 50 Pioneer SX-1050's, and have never had reason to check pin out voltages from the Power Amp board to the output transistors. Pins 21-24, then pins 25-28, then pins 29-32, and the last one pins 33-36. The voltages I am getting on this particular...
    • HankM
    • Thread
    • output transistors power amp board sx-1050
    • Replies: 2
    • Forum: Pioneer Audio
  6. K

    SA-8100 Output transistor insulators

    I'm in the final stages of restoring my SA-8100 amp, having replaced the caps, transistors, and a few fried resistors. It is obvious that something really bad happened to the power amp board, so I'm replacing the output transistors as well, assuming they suffered stress along the way. When...
    • kpmadden
    • Thread
    • output devices power amp board recap and restoration sa-8100 sa8100
    • Replies: 3
    • Forum: Pioneer Audio
  7. tgnadeau

    Marantz 26 - Power Amp Board Rehab

    Output transistor pin out needed from someone with a known good Marantz 26 receiver Hi Everyone - I purchased the Marantz 26 a couple of years ago from eBay. Upon receiving it, it would not power on, tripping the onboard circuit breaker immediately. At the time I ended up removing the power...
    • tgnadeau
    • Thread
    • marantz marantz 26 power amp board receiver
    • Replies: 6
    • Forum: Marantz Audio
  8. Stink Bear

    RS-2004A, finding a short in the power amp board

    I replaced the shorted STK-0050, Q10, Q16, and R46. I powered up on a DBT and still had a short. I de-soldered the power feed to the power amp board and powered up, no short, so it's definitely on the power amp board. If I turn the unit on to "phones" there is no short and the headphone jack...
    • Stink Bear
    • Thread
    • power amp board rs-2004a short
    • Replies: 0
    • Forum: Fisher
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