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Amplifier Problem - Revised Schematic

Discussion in 'Electronic Repair' started by EADGBE, Apr 22, 2008.

  1. James Sweet

    James Sweet Guest


    Last swap meet I went to I saw at least half a dozen scopes under 10 bucks.
    A couple of them were even decent semi-modern looking solid state things,
    probably 10-15 MHz, so this stuff does turn up.
     
  2. EADGBE

    EADGBE Guest

    Richard:

    Sorry about not posting that information. I wasn't ignoring this
    request, I promise. Just hadn't gotten around to it yet.

    I will post the same schematic, but this time with the measurements
    taken from the "good" channel.

    And I will also take measurements at the node(s) you inquired about.
     
  3. EADGBE

    EADGBE Guest

  4. EADGBE

    EADGBE Guest

    .....And I should point out that ALL measurements taken in both
    channels were obtained using chassis ground.
     
  5. David Farber

    David Farber Guest

    I haven't read every follow up message but have you tried removing the
    electrolytic caps and retesting the d.c.? I've seen the d.c. stability been
    thrown off in many amps due to bad coupling caps.

    Good luck.
     
  6. GregS

    GregS Guest

    I completely missed the star explanation. Why not put measured voltages there.
    What is the voltage at collector Q204 on other channel.
    Q205 doesn't seem to be conducting much.

    greg
     
  7. Eeyore

    Eeyore Guest

    Are those the voltages you are NOW getting ?

    Those look correct.

    Graham
     
  8. EADGBE

    EADGBE Guest

    STOP THE PRESSES!

    THE AMPLIFIER PROBLEM HAS BEEN *SOLVED* !!!!!!!!!!!!!!!!!!

    SEE MY POST REGARDING THIS!!!!!!!!

    MANY, MANY THANKS TO EVERYONE WHO OFFERED HELP, TIPS, AND
    SUGGESTIONS!!!!!!!!!!!!!!!!!!!!!!!
     
  9. GregS

    GregS Guest


    Maybe we can improve the design ?

    greg
     
  10. jakdedert

    jakdedert Guest


    And the winner is...????

    jak
     
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