Bad volume pot on old stereo - Replacement?

EH, just how are you "cleaning" it? Trying some "tuner cleaner" shot into both parts - would have been a good start. Good luck on getting it back together and "working".

L.

Good luck. Those were crappy when they were new. I saw bad pots on units that were still under warranty, back in the '70s.

I haven't cleaned it yet. I mentioned that I may try to get some tomorrow. But, tuner cleaner was one of the things I have seen in other posts on the topic that people have used, so I am considering using it.

Nothing like good ole "Quality Control".

L.

Tuner cleaner is a lot safer than WD-40 or other nasty things. It's always worth a try.

What really bugged me was that it was barely a watt per channel, yet they were sold as 200 watts per channel. We bought ECG 102 transistors by the case. We couldn't get enough replacements from Morse/Electrophonic to get them out the door before the warranty expired. Most of the time we just got a credit to use for non warranty parts. I convinced the owner to drop them and Curtis Mathis when it was time to renew the contracts. I was glad that we never sold them. I used to pick them up for spare hardware at Renninger's in Mt. Dora, (a local flea market), from another dealer for 25 cents each after they had sat around for a few weeks.

Trouble with just cleaning it is the track will have a conductive grease. So after cleaning this needs replacing. But unless it's an odd design it shouldn't be difficult to find a replacement two gang pot with switch.

An improvement on the pencil graphite on worn potentiometer track trick. For pots that are worn and it is not possible to replace or adjust the sliders to an unworn part of track. Dismantle to expose the carbon track/s. Make up a paste of one part silica gel to one part of powdered graphite (from locksmiths / hardware stores for lock dry lubricant) into a paste and smear onto the track and reassemble the pot.

More tips on the 2 tips files on my index file below

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I may have a replacement for you. Give the shaft dimension requirements.

Bob

I think this may help >

Or, you could, perhaps, just add an off-switch toggle power switch, to the front or back panel. But as others have suggested, try tuner cleaner first.

Google > I have an old Morse brand FM stereo / phonograph unit (model 74452 for

That's actually a pot and a switch but since you say it is a stereo unit there should be two ganged identical pots and a switch. The two pots may look like one but there will be 6 terminals for the pots and two others for the switch.

In tube days this was a very common unit - now, not so much. See if you can find some local parts distributors who may still have a few in stock. If you can get a 500K unit that should work as well.

Get some tuner and control cleaner from any electronics supplier. DO NOT use anything like WD-40, or you will have to buy a new pot. The original will be impossible to find. You may end up having to replace it with something else, which may require cutting and filing the shaft to fit the original knob. If the pot has any taps on it, then the job will get more complicated if you cannot find an exact match in its electrical specifications.

I found that most of the time, simply cleaning the pot with the proper cleaner will fix it for a long time.

--

JANA _____

I am thinking that I can either clean it, or replace it. This is a 30+ year old stereo, so I would like to replace it, but it is a double-pot. I've googled and such a bit, but I've not been encouraged with the results. So, I'm back to cleaning it. I have gone through some past posts, and it seems that while cleaning is an option, it is not guaranteed to work for any significant period of time, if at all. I may try to get some cleaner tomorrow, but I'd like to know what you may think of the situation.

Details on the pot - It is labelled with the following:

Top Pot - VR-23J M 250Kohm AX2 SF J62X (or J82X, not sure)

Bottom Pot - 3A125VAC 1.5A250VAC

So, as you can see, the pot is double because the top is for volume and the bottom is for power. It clicks when you turn it all the way CCW. Also, one of the wires from the wall plug goes straight to one of the terminals.

Basically, my question boils down to: Is there any hope of replacement, or am I stuck with seeing if I can clean it?

I can post links to pictures if anyone wants a look.

Cheers.

Use sewing machine oil and a hypodermic, no disassembly required.

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You seem to come across totally different 'dirty' pots that I come across. Years ago I realised it was a pointless , even fraudulent maybe, policy of cleaning dirty/crackly pots. I always disassemble now and renovate or on the rare occassion a replacement, rare because of always conflicting physical variations. They nearly always have a worn out ring in the resistive track that no amount of cleaning will sort out. The only exceptions seem to be where the slider has disintegrated/bent which cleaning won't help anyway

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Most pots I "clean" are able to work OK, at least for a while. I have drilled holes into pots so I can inject. I have just let it sit on top and seep into. While I lived on the desert, I noticed added problems with controls. I think its the very fine sand, often found in piles on window sills. I rebuilt my car twice and there is still sand to found in the innards. There is really little to "clean" in pots, but that sand is a real varmin. I don't think I ever saw a pot that had problems that I didn't try to spray. I actually used WD-40 to a large degree longer ago. It was about the same time of the sandstorm days when an Audio Magazine had a piece about WD-40 as being a miracle cleaner. I guess I started to talk about WD-40 just because I used to use it a lot. I like alcohol "cleaning" best, but you have to wait till the water evaporates.

Some pots just need replacing of fixing. Some pots just seem to go on forever without problems.

greg

Try close to a beach where it is very fine sand and salt crystals!! It even eats through CDs - chews them in a spiral pattern if not wrapped.

Exactly what dimensions are you asking for? Simple length and diameter? It's a standard looking size, with a serrated end for the dial to go on...

I can't measure it atm, but I'll do so tomorrow and put a link to a pic for you.

Also, as was mentioned in another reply, it has 6 terminals, 3 on each pot, on the front, as most pots do, and another two, one on each pot, on the opposide side of the pot. Also, there are two terminals at the bottom of the pot on the 3A one, which seems to be for the switch. I don't know what the other two terminals are for. :/

this th> Ech> > I have an old Morse brand FM stereo / phonograph unit (model 74452 for