Markbass LMIII tiny, tiny, tiny scratchy pots.

[chandman1004]

I have a LMIII that has two scratchy pots. Was considering cleaning them with contact cleaner, so i took the lid off the amp. The pot housings are tiny and square. There is a notch in the top corner that might be a place to get cleaner in , but I can't tell.. Anyone seen and or cleaned this type of pot?

 

[BassmanPaul]

The pots are basically sealed - it’s unlikely IMHO that they are contaminated by dust. Scratchy pots are also caused by DC leaking into their circuits. You should take the amp into a MB service place and get it diagnosed properly. Many, many pots have been ruined by the application of so called contact cleaner.

 

[chandman1004]

this is why I just said considering....
I guess I will just take it to a service center.
Thanks!

 

[arbiterusa]

Don't do it. You'll trash the pots. They'll still work, but they'll be super loose and able to be moved even by vibration.

 

[DWBass]

Do what I did. I sat in my living room and turned the knobs back and forth for about an hour. Scratchiness went away. I bought a LMIII a couple months ago. The volume knob was scratchy. I just turned the knob back and forth for about an hour.

 

[Red Planet]

Do what I did. I sat in my living room and turned the knobs back and forth for about an hour. Scratchiness went away. I bought a LMIII a couple months ago. The volume knob was scratchy. I just turned the knob back and forth for about an hour.

+1000 this has worked for me many times.

PSA when cleaning pots always use Lubricated Contact Cleaner.

 

[chandman1004]

Wow an hour. Sounds like fun. So just turn them for an hour, no cleaner or lubricant?

 

[Red Planet]

Wow an hour. Sounds like fun. So just turn them for an hour, no cleaner or lubricant?

Turn them til they quit scratching, 10 minutes tops.

 

[DWBass]

Wow an hour. Sounds like fun. So just turn them for an hour, no cleaner or lubricant?

Well maybe not an hour but I was watching TV and I just turned the knobs while watching. I didn't have any cleaner/lube and according to a post above, the pots are sealed or not easily accessible anyway. Doesn't matter. My knobs are noise free.

 

[chandman1004]

Ok, thanks

 

[GUY DES ROSIERS]

I have a LMIII that has two scratchy pots. Was considering cleaning them with contact cleaner, so i took the lid off the amp. The pot housings are tiny and square. There is a notch in the top corner that might be a place to get cleaner in , but I can't tell.. Anyone seen and or cleaned this type of pot?

I bought a month ago a used LMT800, the Gain 1 was very scratchy and also the Master Vollume. Since I know that they are sealed pots I removed the knobs and saw that there was a very small hole at the base of the shafts. So, this morning I sprayed DeoxIt D5 in these small holes and turn the shaft of the pots for about a minute or so and voilà no scratchy noise anymore. Hoping this will help those having this problem.

 

[GUY DES ROSIERS]

I bought a month ago a used LMT800, the Gain 1 was very scratchy and also the Master Vollume. Since I know that they are sealed pots I removed the knobs and saw that there was a very small hole at the base of the shafts. So, this morning I sprayed DeoxIt D5 in these small holes and turn the shaft of the pots for about a minute or so and voilà no scratchy noise anymore. Hoping this will help those having this problem.

Yesterday I forgot to mentioned that my first idea was to get the cleaner in the pots by spraying the shaft hoping the cleaner will get in the pots that way. I did that also so not sure if the cleaner got in that way only or both ways (Shaft + the small hole at theb ase of the shaft). The important thing is it worked.

 

[GUY DES ROSIERS]

What ever said agedhorse my positive experience with DeoxIt D5 with my LMT800 is now and for two weeks today positive my pots are scracth free and works just fine.