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Looking for 1990 Kenwood A-54 amplifier parts

flippineck

Sep 8, 2013
358
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Sep 8, 2013
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Fault symptoms:

Volume knob (which is motorised and can rotate under IR remote control command) has a number of regions of travel where loads of dropout (R, L and both channels randomly) occurs upon movement. Can only reliably set volume at certain levels.

Dropout also occurs sporadically when turning balance and bass / treble pots.

Amplifier is pretty old (I bought it new around 1990)

It sat in close proximity to a regularly used ashtray on an untidy desk for the first 10 years of it's life.



I'm figuring from the above that probably, the resistance tracks and wipers in the pots have become damaged due to cigarette ash ingress. I have opened up the amp and blown seven bells out of everything with a compressed air line, did that a few years back, it fixed the problem at first but now it's come back.



So I'm thinking about replacing the treble, bass, balance and master volume pots.



Service manual says:


VR1 = R29-5045-05 'potentiometer master volume'
VR2 = R05-5035-05 'potentiometer balance'
VR3,4 = R06-5198-05 'potentiometer bass, treble'

Service manual:
http://s000.tinyupload.com/?file_id=63340205154566220588


Can anyone suggest a source for these parts, pref UK based or will-ship-to UK

Am looking at http://stores.ebay.com/joeoldaudiovintageelectronicsonly/ at the mo, don't know if there are any other likely sources out there?
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
I'm not able to look at the service manual right now. Are there pots log or linear, and what resistance?
 

flippineck

Sep 8, 2013
358
Joined
Sep 8, 2013
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358
VR1 master vol appears to be listed as "100KB", twin gang, with two wipers per gang (maybe one's a trimmer?) No indication of lin or log. It's also shown as ganged to a diode, maybe that's the flashing LED on the knob. Also there appears to be an integrated motor and motor drive IC 'IC3'

VR2 balance shown as '200KB' single gang but again with two wipers, one maybe a trimmer. No indication of lin or log

VR3, VR4 the tone pots '100KB' twin gang with single main wipers. No indication of lin or log
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
Hmmm, very weird.

I'd seriously be trying some contact cleaner or similar on these. They look dangerously like custom devices (well, the master volume one does)
 

flippineck

Sep 8, 2013
358
Joined
Sep 8, 2013
Messages
358
Someone once suggested the trick of opening a pot up, and carefully scribbling on the resistance track with the softest of graphite pencils.. as a last resort after contact cleaner if that didn't do the job. Think I'll only try that just before chucking the unit in the skip.

If it wasn't cause of sentimental value I'd just bin it already but it's been with me thru thick and thin.
 
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