Hi, So my Cambridge Audio A500 amp has developed some static in left channel and tapping on volume knob often makes it go away for a bit. I have used the amp as just a pre amp and it still does the same thing so I dont belive its in the Amplifier section. I took have cleaned the pot with deox it few times and that hasnt solved it. I took Amp apart to see if possibly bad solder joint on the board where the pot attaches and that looks fine to me. Im at a loss. I was going to jus tse ebaout ordering a new volume pot for it but i cant seem to find correct part. Its made by Seawell for CA and looking for a suitable replacement has been daunting. Anyone have any suggestions?
Have you also cleaned all the other controls and pots?
Also the volume pot could be worn out, not just dirty.
A new pot would have to be mechanically able to fit, one way or another.
Some photos of the pot might help.
Also the volume pot could be worn out, not just dirty.
A new pot would have to be mechanically able to fit, one way or another.
Some photos of the pot might help.
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Yes have thoroughly cleaned everything. I kind of was just hoping to find a replacement part however no clue. I know its a dual gang 100k pot thatsa it
Is the volume pot pcb mount, or is it panel mount with solder lugs and flying leads?
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HI Yes Ive cleaned all pots etc. I was trying to just find replacement part but not having luck. Its dual gang 100k motorized potentiomenter
Ok, can you estimate or measure the pcb hole pattern?
Of course, a panel mount control could be used, with leads connecting it to the pcb.
It appears that the 100k volume control may actually be a linear pot (not a log type),
since the 20k balance pot is connected from the volume pot wiper to ground. This would
form an audio taper when connected to a linear pot, and would improve tracking at low cost.
Of course, a panel mount control could be used, with leads connecting it to the pcb.
It appears that the 100k volume control may actually be a linear pot (not a log type),
since the 20k balance pot is connected from the volume pot wiper to ground. This would
form an audio taper when connected to a linear pot, and would improve tracking at low cost.
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Yes, if the pot has a metal housing you should try that before giving up,
even if as you say the noise seems to be in only in one channel.
But the amp is 20 years old, so wear is likely.
An example of a possible sub:
https://www.amazon.com/Potentiometer-Alpha-Dual-100K-Linear/dp/B00E3X6UPO
even if as you say the noise seems to be in only in one channel.
But the amp is 20 years old, so wear is likely.
An example of a possible sub:
https://www.amazon.com/Potentiometer-Alpha-Dual-100K-Linear/dp/B00E3X6UPO
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So after checkng the solder joints etc of the volume i realized the issue at least seems to be the tone control board. When tapping the volume knob or any other knob the left channel static comes and goes. If i push slightly down on right hand corner of tone board it works. There isnt a screw there or a standoff missing as I hoped. Is there a way I can by pass the tones control and possibly go right into the volume pot?
Does the tone bypass switch stop the noise, when in bypass mode?
That would be the simplest solution, if it does.
That would be the simplest solution, if it does.
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No unfortunately. It seems any touching of the knobs makes the static come in and out but pressing down on right hand corner a little it works fine. I was just looking at the tone board schematic to see if I can just go right to the volume pot somehow.
Try using the eraser end of a pencil (or other plastic tool), to gently touch various parts of the tone board,
and the parts mounted on it. Find the most sensitive spot on the board.
and the parts mounted on it. Find the most sensitive spot on the board.
I have its the furthest point of the tone board. If I push down on it it works. Right now I put some blue tacky stuff and wedged it between the tone board and main board where they meet. It is a temp fix. maybe a bad trace in the tone board possibly from someone over tightening maybe. Is there a way can take a picture and show it here
Odds are the whole board is moving then. Have you cleaned the four plug-in connectors that go to that board?
Also one of the connectors could have a pin with a loose crimp. If nothing else, unplug and plug back in each
plug to wipe the contacts.
Try touching each wire going into each of the four connectors with an eraser.
Also one of the connectors could have a pin with a loose crimp. If nothing else, unplug and plug back in each
plug to wipe the contacts.
Try touching each wire going into each of the four connectors with an eraser.
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