Pioneer SX 780 Relay Keeps Clicking

Discussion in 'Pioneer Equipment Database.' started by micaiahm, Feb 4, 2017.

  1. micaiahm

    micaiahm Member

    North of City, New York
    I recently moved and my 780 has stopped working. The relay clicks on about 6 seconds in, but then keeps clicking on and off continuously. (Had a similar issue with my 880 but that was fixed by replacing the transistor that drives the Relay, didn't work on 780.) This receiver has been completely recapped based upon MTF's parts list sticky. Been reading the forums and trying everything that has worked for everyone else, nothing yet. Now I need more help.

    What I have done:
    Check for cold solder points - all good.
    Reflowed solder on power regulators and output transistors just to check.
    Replaced Protection Relay with a spare that came from working unit.
    Replaced Q26
    Checked output resistors- good
    Checked voltages on power regulators and output transistors:

    Left Right
    1. -1.2, -1.2
    2. -39.7, -39.6
    3. 0, 0
    8. 0, 0
    9. 39.7, 39.6
    0. 1.3, 1.2

    E C B.
    Q19 38.8, 49.4, 39.5
    Q20 -38.9, -50.9, -39.5
    Q25 13.5, 25.8, 14.2
    Q26 0, 50.4, .1

    P3004 Voltages per schematic

    Any help or direction is appreciated.

    Edit: realized I posted this is wrong place, have moved.
    Last edited: Feb 5, 2017


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