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multiplex

  1. Richard P

    Sansui 5500 No Stereo, Clear Mono

    I'm working on a Sansui 5500 receiver and am having an issue with the FM Multiplex board. I get good FM reception but no stereo. I have a good 19 kHz, 3 Vrms signal after TR402 and a 38 kHz, 1Vrms signal at the base of TR403 but no 38 kHz on the collector of TR403. DC voltages around the...
    • Richard P
    • Thread
    • 5500 mpx multiplex sansui stereo stereo separation tuner
    • Replies: 45
    • Forum: Tuners
  2. Carbsandcaps

    Are all 19kc coils created equal?

    Working on my Sansui 250 tube receiver that I’ve been listening to for a while now. Did a full recap and it sounds great but the multiplex never worked. I swapped it out today and decided to take a look at it and found 0v on pin 6 of the 6aq8. Turns out the primary coil of T7 is open. It’s the...
  3. Carbsandcaps

    Sansui multiplex problem

    Working on a Sansui 1000 (not 1000a) tube receiver. When in multiplex mode one channel is muffled and slightly lower than the other. I’ve traced it to the 12au7 tube I’m assuming that splits the stereo signal. I swap the inputs to the grids and it does not swap channels. I swap the outputs at...
  4. david winter

    QR-6500 / QRX-6500 : stuck with a different version of the F-1322 FM decoder

    Hello, I am close to finish restoring a QR-6500 (serial is 211091683 if this can help with differences / mods). I need to verify the position of a strap (see picture below) on the solder side of the F-1322 decoder board. The service manual seems to have the right schematic (at least something...
  5. jpatti75

    Shorting Bar? - Motorola HK 45-2 Tuner

    Hi gang, What be the purpose of the shorting bar in this Motorola tuner diagram, and when is it necessary to move it to the Mono or Stereo position? Does it come into play when using a multiplex adapter for FM stereo? Ignorantly yours, JP
    • jpatti75
    • Thread
    • hk45-2 motorola multiplex tuner
    • Replies: 3
    • Forum: Tube Audio
  6. Geek

    MX-110 MPX Matrix Issues

    Hi Folks, Gotta MX-110 on the bench here (Ser. 188Z6) with a unique issue I have not encountered before. Problem: All (including FM Mono) works awesome. MPX position delivers a mono L-R (left minus right, the info contained on the 38KHz DSB subcarrier) to the speakers. There appears to have no...
    • Geek
    • Thread
    • matrixing mcintonsh mpx multiplex mx-110 tuner
    • Replies: 6
    • Forum: McIntosh Audio
  7. tusntuk2

    Sx-626 FM Stereo problem - Does this sound familiar? Need some help.

    Just finished recapping a lovely little SX-626, and the FM board doesn't want to go stereo. The Muting switch sometimes works, sometimes cancels all strong signals and goes silent. The Stereo light flickers while tuning, sometimes indicates stereo on weaker stations, but often does not glow on...
    • tusntuk2
    • Thread
    • awe-011 decoder fm stereo mpx multiplex muting circuit stereo light sx-626 tuning cap
    • Replies: 5
    • Forum: Pioneer Audio
  8. johnfalc

    Gifted 800C coming back to life ...

    Pleased to be making progress on a Fisher 800C that was gifted to me in pretty sad shape. The Fisher 400 and 500C (same as the 800C but without an AM section) were our standard bench receivers when I was running service operations for Pacific Stereo in the 70s because they were so reliable. I'm...
    • johnfalc
    • Thread
    • fisher 800c multiplex
    • Replies: 1
    • Forum: Fisher
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