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Old 21st Nov 2022, 12:15 pm   #1
RDWER123
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Default Crackly volume knob Pioneer A-400

As above, I bought an old A-400 through Gumtree, which I'm absolutely thrilled with, but the volume pot it very scratchy.

I realise this is a beyond basic question for you experts, but I have a tin of WD-40 specialist contact cleaner (not the normal stuff - I know that much at least!) but am unsure whether I need to pull the knob off and spray in there, or do I need to open up the case and spray it from behind as it were?

Sorry, aware this is very basic stuff...
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Old 21st Nov 2022, 12:44 pm   #2
Goldieoldie
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Default Re: Crackly volume knob Pioneer A-400

You will need to gain access to the pot.
When you do look for any gaps on tge casing to spray the cleaner inside .
Take care not to overspray onto the front if there is a dial etc.
One sprayed in give the know a few twiddles .
Sometimes IPA ( Alcohol ) is better at cleaning .
Cheers
Pete
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Old 21st Nov 2022, 6:36 pm   #3
Silicon
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Default Re: Crackly volume knob Pioneer A-400

Sometimes the casing of the potentiometer has small holes or gaps which will allow you to spray the contact cleaner into the internals using the 'straw' tube.

You will probably have to open the amplifier to see the holes.
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Old 21st Nov 2022, 6:39 pm   #4
Analogue man
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Default Re: Crackly volume knob Pioneer A-400

To clarify that yes you do need to remove the cover to access the guts of the volume control, there should be a gap in the volume controls casing where the connections to it come out, you should spray a little cleaner in there and work the knob over its full travel. If that doesn't cue the problem, try a little more cleaner and repeat the knob turning. Make sure that the amp is disconnected from the mains first though.
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Old 21st Nov 2022, 8:02 pm   #5
paulsherwin
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Default Re: Crackly volume knob Pioneer A-400

The degree of dismantling required depends on the design of the pot. Often there is a gap where the contacts come out. You need to get cleaner on the carbon tracks, and also the wipers on the central shaft. As others have said, exercise the control vigorously after spraying the cleaner.
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Old 25th Nov 2022, 10:39 pm   #6
nigelreltub
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Default Re: Crackly volume knob Pioneer A-400

Couple of pic's an A400 volume/balance pot. I believe these are inherently problematic.

Hen's teeth if it can't be brought back to life

Goodluck @RDWER123 any update?
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