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This is starting to bother me... I have both D5 and F5, and I've tried both to fix scratchy pots on amps from the 60s to the 90s.
The problems go away for a few days and then it's back to scratch-city 9 out of 10 times. Is that normal?

Which part of the pots are you spraying?

Cleaner/lubricant should go in the little indent above the middle lug in the pic below.

level3 wrote: ↑

Wed Mar 06, 2024 12:58 am

This is starting to bother me... I have both D5 and F5, and I've tried both to fix scratchy pots on amps from the 60s to the 90s.
The problems go away for a few days and then it's back to scratch-city 9 out of 10 times. Is that normal?

Your scratchy pop syndrome is more likely caused by capacitors in the circuit that are failing, aka not efficiently blocking DC current to the potentiometer.

B.T. wrote: ↑

Wed Mar 06, 2024 8:28 am

Your scratchy pop syndrome is more likely caused by capacitors in the circuit that are failing, aka not efficiently blocking DC current to the potentiometer.

Thanks.
If it's DC hitting the pot, why does the Deoxit work for a few days?

Just for a sanity check, after you spray the Deoxit, are you running through the full range of the pot a few times? You want the wiper to spread the Deoxit across the entirety of the contacts so that it knocks away the corrosion and builds up a layer of lubricant/protectant.

level3 wrote: ↑

Wed Mar 06, 2024 11:35 am

B.T. wrote: ↑

Wed Mar 06, 2024 8:28 am

Your scratchy pop syndrome is more likely caused by capacitors in the circuit that are failing, aka not efficiently blocking DC current to the potentiometer.

Thanks.
If it's DC hitting the pot, why does the Deoxit work for a few days?

The question you should be asking yourself is why are these pots that are not exposed to the elements (aka in an enclosed chassis) keep getting scratchy noises after you use a solvent like that to clean them? So by now they should be clean right?

I would be willing to wager they were acceptably clean before you used Deoxit. I haven’t used a pot cleaner in years on a pot that lived in an enclosed chassis unless there looked like there was a lot of internal corrosion or a really really old circuit like 1920’s-30’s old.
I do use the stuff on open faders, those can get really grimy. But I will disassemble the entire fader and go to town on the tracks, same with questionable pots come to think of it.

On chassis pots I usually just replace the offending caps and the scratch goes away. Fwiw those can start failing after 20-30 years. Your amps are of that vintage.

Are you running the amp in the same room the whole time? It could be static electricity building up. The room i work on amps in has a static issue. It's very annoying.

Also, I don't use deoxit for pots. I only use it for metal to metal contact points like jacks and switches. I don't like the way deoxit kills the lubricant in pots and makes them feel terrible after awhile.

I use stuff called Max Pro Super Lubricant. I especially use it for vintage amp and guitar pots and vintage synthesizer pots and sliders.

OffYourFace wrote: ↑

Wed Mar 06, 2024 9:07 pm

I use stuff called Max Pro Super Lubricant. I especially use it for vintage amp and guitar pots and vintage synthesizer pots and sliders.

Like… the mechanical lubricant stuff used on chain drives and the like?

Wow, that’s interesting; I’d never have thought to try that on electronics

I usually use Caig F100L in the little dropper bottle

øøøøøøø wrote: ↑

Thu Mar 14, 2024 11:47 am

OffYourFace wrote: ↑

Wed Mar 06, 2024 9:07 pm

I use stuff called Max Pro Super Lubricant. I especially use it for vintage amp and guitar pots and vintage synthesizer pots and sliders.

Like… the mechanical lubricant stuff used on chain drives and the like?

Wow, that’s interesting; I’d never have thought to try that on electronics

I usually use Caig F100L in the little dropper bottle

Yep. A little goes a long way, just a couple drops. It doesn’t dissipate like deoxit obv but it flushes out the debris and keeps things feeling smooth.

You gotta shake the can before you use it.

Super interesting, great tip!

I guess I’m a bit too narrow-minded to think of off-label uses like that (or maybe too influenced by horror stories of people using WD-40 on pots)

Curious where you learned about that, or did you just try it in your own?

øøøøøøø wrote: ↑

Fri Mar 15, 2024 11:22 am

Super interesting, great tip!

I guess I’m a bit too narrow-minded to think of off-label uses like that (or maybe too influenced by horror stories of people using WD-40 on pots)

Curious where you learned about that, or did you just try it in your own?

When I was doing synth repair, a tech we respected that specialized in restoring vintage Buchla and Synthi AKS & VCS3 synths tipped us off to it.
There are still some old synth sliders that it's not right for like some old Rolands and the big crappy CTS sliders in old Arp 2600s (WD40 actually works on these!) but it works great on all rotary pots in my experience. Like a minimoog for example... After drilling a hole (just big enough for the straw tip) in those Allen Bradley pots with a very short bit (to minimize debris), just squirt a few drops in and turn them a few times.

Sounds like just what I need for the old A-B in a Maestro Boomerang wah

Though I’m more likely to just disassemble the pot by bending the tabs, give it a good cleaning, then re-lube

Excited to try it!

Um... Won't oil/lubricant build up and eventually attract more dust/grime and you'll be right back where you started?

Isn't that the whole point of Deoxit/Contact Cleaner?

Quite the contrary, in many cases.

Hot-molded carbon element pots (like the ones we're discussing... the old Allen-Bradley Type J and the newer PEC equivalents) require lubrication or the wiper will actually begin to scrape carbon dust from the track. It's this carbon dust that causes the scratchy crackling behavior, as those pots are sealed to prevent dust intrusion

These pots come/came lubricated from the factory, and if the lubrication becomes compromised (or if they have to be disassembled for cleaning) then it most be restored or the pot will just get scratchy again very quickly