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60 cycle hum

  1. Yamaha5000

    Yamaha CA-1000/CA1000II Power Supply and Protection Circuit Diagnostics, & Lower SNR values with the QA403

    With the DVM + lead on the Base of TR708 and the - lead on E: On the V scale I read 15.32vdc and the relay is off On the mv scale the relay coil becomes active I can use the V and mv scale selector to act like a switch to turn the relay on and off. FYI the Emitter to E measures 15.84vdc...
    • Yamaha5000
    • Thread
    • 60 cycle hum crosstalk internal hookup wire power supply power supply caps protection circuit qa403 snr yahama amplifier yamaha ca-1000
    • Replies: 358
    • Forum: Yamaha
  2. JB8

    ROTEL ROTEL - Ground Hum From Milan to Minsk

    Forum friends. I have a little ROTEL RX-200A with the dreaded ground hum. It's 60 cycles, across both channels, and it's like a mouse in a garage - every time I think I have it cornered I'm foiled again. Here's where we're at thus far: Replaced the main amp transistors and four of it's caps...
    • JB8
    • Thread
    • 60 cycle hum ground hum receiver rotel rotel rx-200a
    • Replies: 65
    • Forum: Solid State
  3. cecilk

    Airline GAA-2940 - Power Supply 60 Hz Hum

    I'm repairing an Airline (Montgomery Wards) GAA-2940 console and after noticing the sound quality was a little off tone-wise and distorted, I have tested and replaced all electrolytic capacitors in the circuit (many were way off tolerance and quite leaky). The console now works fine - AM/FM...
    • cecilk
    • Thread
    • 60 cycle hum console stereo power supply
    • Replies: 35
    • Forum: Solid State
  4. L

    yet another hum elimination question

    I'm trying to eliminate a 60hz hum in a 1960 Motorola console stereo. I've replaced the power caps, the rectifier, the 12AX7s, and put in a grounded plug. I will be replacing the power tubes with a matched set of EL84s in the coming months (likely the JJ EL844s), but somehow I don't expect this...
  5. david24x7

    Weird Hum from Heathkit SP2 Preamp

    Hi. I just finished recapping all the electrolytics in this preamp that I've been using for some time (better late than never). I had some issues with recitfier diodes but I've worked that out and I had eliminated the 60 cycle hum that given me trouble. After I got it back on the shelf (and...
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