Fixing an old amp

Discussion in 'Home Theater Projects' started by Travis-J, Jul 29, 2003.

  1. Travis-J

    Travis-J Agent

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    I bought a cheap old amp, and would at some point like to use it perhaps for some bass shakers. When I plug speakers into it and an input source, I get sound out of the speakers really quietly, and the volume control won't adjust the volume, could this be a simple fuse? Any Ideas?
    If I have to throw it out oh well, cost me $15 with a pair of crappy speakers.
     
  2. Michael R Price

    Michael R Price Screenwriter

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    Try bypassing or replacing the volume control and any other switches/potentiometers the signal goes through, they may have bad contacts. If that doesn't work, the amp may have more serious, yet still easily fixable, problems. (Example: dead power supply.)
     
  3. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Are you plugging the speakers into the "tape out" jacks ?
     
  4. Cameron_Peck

    Cameron_Peck Stunt Coordinator

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  5. Michael R Price

    Michael R Price Screenwriter

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    Cameron, what's failing about it? I think the most obvious problem would be that the electrolytic filter capacitors dried up over time. This would cause a weaker sound and maybe some hum and noise because of not providing adequate DC power. Replacing those capacitors could fix the problem.. if they are the actual problem, that is. Check the voltages (AC at transformer secondary and DC on power rails) to make sure the rest is working, though. If the power supply's good and it still doesn't work there could be other components in the rest of the circuit that failed.

    (And yes Travis, if there's an incorrect connection on the amp that could cause the problem you described. Check to make sure that the input is not connected to the phono jack, and the speaker wires are solidly screwed into the binding posts.)
     
  6. Cameron_Peck

    Cameron_Peck Stunt Coordinator

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    This has only happened twice. The sub was putting out no sound and the LCD on the receiver got dim. When I turned it off and back on it started working correctly. I was not pushing it hard either time this happened.
     
  7. Travis-J

    Travis-J Agent

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    I don't have a lot of options on where to connect what.
    Hehe, binding posts, thats funny, I've never seen speaker wire inputs like these. I think when I first bought it the volume worked for the tuner, but I didn't test anything else. My choices for inputs are tape1,2 or phono I believe.
    I am going to fiddle with it a bit more today, I don't know a lot about amps, I think the first thing I will try is to replace all the fuses.
    How would I bypass the volume control?
    Would it help if I put the brand and part number?
     
  8. Travis-J

    Travis-J Agent

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    I have figured out part of the problem, only one side works (either right or left). When I have it really quiet I can hear both speakers, but as I turn it up the volume on one side drops to nothing while the other increases normally.
    So if all else fails I have two working channels.
     

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