Potentiometer Wiring

Discussion in 'General Electronics Chat' started by jfish, Mar 6, 2011.

  1. jfish

    Thread Starter New Member

    Mar 6, 2011
    7
    0
    I'm trying to replace a 5 pin stereo (dual gang) pot from a pair of PC speakers with a new 6 pin pot for a project that I'm working on. The 5 pin pot is actually a six pin pot but it's sitting on a circuit board that appears to combine two of the six terminals, making five terminals that connect to the rest on the circuit (amplifier). I have not removed the original pot from the amplifier yet (5-wire flat ribbon cable) because I wasn't sure if it would be easier to figure out how to wire this thing if it's still connected. The 5/6 pins on the original pot are all in one straight line, not in two rows like you see on a typical 6 pin pot, which makes it difficult to determine which pins belong to each channel.

    My question is, what two pins could be common on a dual gang pot since the original pot goes from 6 to 5 pins? Would it be ground, wiper etc? How would I test the original pot with a DMM to determine which pins are for which channel and, within each channel, which pin is the wiper, input, output etc.?

    Thanks in advance for any help that you can provide.
     
  2. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Do you know the function of the pot. that you are replacing (volume, balance, etc)? The most likely connections will be different, depending on what the pot. is doing. For instance, in a volume control the anticlockwise end of the tracks on both channels might be grounded. Balance and tone controls have more possibilities.

    If you have access to an oscilloscope there might be some merit in probing the voltages on the pot pins with the pot set to different positions. It may help to apply a signal to one channel only, then swap sides. Again, this might be simplest for a volume control.

    Whatever you do, make a clear record (photo?) of the pot. connections before you remove it. You may regret it if you do not.

    If the pot. is still basically functioning after it has been removed, simple tests with an ohmmeter should soon sort out what is what. You should therefore try to remove it without mangling it, unless it has already totally failed.

    Finally, if you are not already aware of it, the usual pot. function has a slider or wiper which contacts the resistor track at different points between the two ends according to the control position. Turned fully anticlockwise, the resistance between the slider and one of the contacts is very small, but the resistance from the slider to the other end of the track is approximately the pot. nominal value. At the fully clockwise setting the situation is the other way around. The resistance between the two track ends should not change much as the control moves. These observations of course refer to a pot. on its own, not connected to other things.
     
  3. jfish

    Thread Starter New Member

    Mar 6, 2011
    7
    0
    Oh, sorry...it's a volume control. Also, the original pot is still completely functional and it can be easily removed from the amplifier because it's connected via a 5 wire ribbon cable. I don't have access to a oscillator but I'm guessing this will be most easily tested by first disconnecting the original pot from the amplifier so that I'm not getting false readings from the rest of the circuit. So that I don't have to go through the trouble of removing the pot from the little circuit board that it's attached to (which connects two of the six pins to make 5 total going to the amplifier via the 5 wire ribbon cable), I'm wondering which two of a six pin, dual gang pot might most likely be connected together.
     
  4. nigelwright7557

    Senior Member

    May 10, 2008
    487
    71
    2 pins will connected together and to audio ground.
     
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