Marconi Cabinet Radio Potentionmeters

[HolderAccount]

Hi,

I wanted to replace the Volume and the On-Off tone potentiometers since they are very hard to move now but still work. What part numbers would I need and where can I find the POTS?

Thanks

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[garykuster]

Have you tried to clean and lubricate them already. DeoxIT should help

[HolderAccount]

No I havent…. Where can I find DeoxIT?. and will it permanently fix my issue

[HolderAccount]

I’ve used electronic cleaner, or electrical contact cleaner etc. with a lot of success. Lubricates and cleans. I think I got my most recent spray can in Canadian Tire. You need to get in to the back end of the pot and squirt into a space using the thin plastic tube supplied, so that the cleaner penetrates inside the shell. It dries leaving no trace behind and is harmless, but highly flammable while wet. So don’t switch on for ten minutes after spraying and exercising the pots! 🙂

[HolderAccount]

Awesome!. I have electronic contact cleaner in my shop will try this now.

Thanks for all the replies 🙂

[Rick D]

Hello Paxton
I use WD-40 most of the time ,it has always worked fine for me ,have a great
Christmas all the very best Rick

[HolderAccount]

I’d rather not use WD40, because It leaves a residue which can eventually gunge up with dust etc.

[HolderAccount]

My experience with stiff (hard to turn) controls such as volume or tone is that the problem is NOT in the resistor section so spraying anything in there doesn’t help and may actually hurt by causing a different problem. The issue is usually that the lubricant between the control shaft and the mounting bushing has hardened. To cure this, tip the radio with the control shaft turned “up”. Warm up the shaft/bushing with a heat gun or soldering gun (don’t get all crazy and melt anything). Once it’s warm to the touch, put ONE drop of penetrating oil between the shaft and bushing and gently work the shaft by turning it until it frees up, then follow that up with ONE drop of a light oil and work it in. This usually fixes them permanently.

NOTE : if you use too much oil, it will flow thru’ and contaminate the resistance strip.

cheers

[HolderAccount]

Update.

I may have sprayed to much electronic cleaner on the POTS. The on/off and volume move pretty freely now, but no power now when turning the system on. 🙁

Nothing is powering up. crap!

any suggestions?

[HolderAccount]

Check the on/off switch for continuity. But you may simply have a secondary fault somewhere. I recently put a scope on my project to do a line-up, and the thing died on me. Turned out to be a paper cap, nowhere near where I had attached the probe, which had gone shorted on me. DC resistance 350 ohms instead of infinity, and it had pulled the PSU power output down to almost zero. I replaced it and the thing was live again. The scope probe was purely coincidental.

[Author]

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