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canadianicon25 19th June 2013 06:08 PM

pot--trying to find
 
trying to find this pot:
it's dual with what looks like 8pins. it is a volume control pot for an old hk730. can anyone help me with finding a replacement?

http://i890.photobucket.com/albums/a...pot_volume.jpg

Mooly 19th June 2013 07:12 PM

The "extra" connections will be for a loudness compensation circuit which means finding a replacement will be difficult/maybe impossible. A standard pot will work OK but you lose that loudness feature which seemed popular on amps of a certain vintage.

What's wrong with the pot ?

If its noisy and crackly then I would say that one of that style could be opened up successfully. You have to bend the metal tabs back to disassemble but it should be do-able. The carbon track is cleaned with iso on a cotton bud and the wiper cleaned, re-tensioned and bent slightly so that it runs across unused carbon track.

If you want to fit a normal dual gang replacement then you need one of the correct value (resistance) and of the correct "taper" which is logarithmic for a volume pot.

canadianicon25 19th June 2013 07:35 PM

the pot sticks. it doesn't crackle. its hard to turn.

csom 19th June 2013 08:06 PM

1 Attachment(s)
Perhaps you can find this variant of this potentiometer ( photo in the attachment) .
I found this in a local shop in India.

I asked for centre-tapped dual potentiometer and they instantly gave it.

It's 80+20K. I used that in my discrete audio amp kit earlier. It is used to implement the loudness effect as Mooly rightly pointed out.

All the very best. :)

gain wire 19th June 2013 08:20 PM

One word: ebay. There are sellers there who deal only with audio parts, used and new. I can look for you later on, but it's pretty straight-forward.

Also, I remember correcting sticky pot shafts but simply heating it over s lighter. Maybe a matter of a few seconds, enough to liquify the grease. It might return back to its "sticky" state sometime thereafter.
Kudos on saving a vintage piece of audio.
I have a HK 495i that's my "daily driver". The only problem I find with it is the leakage in the switching path between TAPE 1 and TAPE 2.

Hearinspace 19th June 2013 10:39 PM

Quote:

Originally Posted by csom (Post 3532018)
Perhaps you can find this variant of this potentiometer ( photo in the attachment) .
I found this in a local shop in India.

I asked for centre-tapped dual potentiometer and they instantly gave it.

It's 80+20K. I used that in my discrete audio amp kit earlier. It is used to implement the loudness effect as Mooly rightly pointed out.

All the very best. :)

Here is a page for someone selling them on eBay

Enzo 19th June 2013 11:46 PM

Sounds like your shaft is bound up in the bushing. Some heat might loosen it enough to turn, and just oozing some fresh lube into the bushing will probably free it up with a little effort. Even some WD40 would probably soften the old hardened lube.

And on many older stiff pots, just spraying my Deoxit into them to clean also thins out the lube and frees the motion.

Mooly 20th June 2013 06:33 AM

Some good advice for you in the above posts. A drop of lube on the shaft bearing has to be the first step.

Fast Eddie D 20th June 2013 08:12 PM

Rat Shack now sells stereo volume controls with a loudness tap. I believe the value is 100K. It looks like it's the same one they sold decades ago.


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