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Fisher TX-50 Rebuild - Audio Issue

Discussion in 'Fisher' started by Pioneer Vir, Jul 9, 2018.

  1. Pioneer Vir

    Pioneer Vir AK Subscriber Subscriber

    Rebuilding a Fisher TX-50 Amplifier that I recently picked up from Frannie's moving sale. Pretty much done with it for the most part and I'm having an audio issue with it. Balance pot has a scratchy spot at "3 o'clock" that I just can not get rid of. I have cleaned it and cleaned it over and over again with DeOxit but I just can't get rid of that scratchy area. Rest of the pots cleaned up nicely and they're all working smoothly.

    Both audio channels are working correctly in Mono but the right channel is very weak in Stereo. I've cleaned the Mono/Stereo switch with no change. All voltage readings are good with the possible exception of Audio Control Amplifier Right Output and Right Mode Switch. Not really sure. Readings between Left and Right are as follows:

    Right Output in Mono: 15.25V
    Right Output in Stereo: 11.92V
    Right Mode Switch in Mono: 17.43V
    Right Mode Switch in Stereo: 13.41V

    Left Output in Mono: 14.91V
    Left Output in Stereo 16.48V
    Left Mode Switch in Mono: 17.17V
    Left Mode Switch in Stereo: 18.99V

    Still troubleshooting it but if anyone has any ideas or recommendations, I'm all "ears".

    Don

    Fisher TX-50 Before 1.jpg Fisher TX-50 Before 2.jpg Fisher TX-50 Before 3.jpg Fisher TX-50 Before 4.jpg Fisher TX-50 After 1.jpg Fisher TX-50 After 2.jpg Fisher TX-50 After 3.jpg Fisher TX-50 After 4.jpg Fisher TX-50 Audio Control Amplifier Schematic.jpg Fisher TX-50 Main Chassis Schematic 1.jpg
     

     

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