Place for studio effects threads? United Audio LA-4

[blearyeyes]

UREI / Universal Audio LA-4 Compressor / Limiter

This is a simple project in as much as electronically it functions well. The hard part is I need to repair damage that was apparently caused by dropping the unit on its face. Meter bezel is broken but I have all the plastic. That's how the meter is mounted.

The pots and switches are ( I think) worn out. I used this in my studio as is for years, would be nice to fix it. Had to wiggle the output pot to get it to work right and the concentric switch makes noise as I recall. There is what looks like white goo visible inside the back of the pots. Also need to find schematic as the pots have no markings on them.

What is the best pot /switch cleaner ?

[mozwell]

some info to help you

[The Dude]

What is the best pot /switch cleaner ?

I like Chemtronics DPL (Deep Penetrating Lubricant). I've used it for years and it's always worked well for me. However, it's not readily available in most stores.
Deoxit is also a very good cleaner/lube and Radio Smack has carried it for quite some time now. Usually sold as a two part application- a cleaner and a lubricant.
Also, if you have access and the pots/switches are not too well sealed, use a "canned air" product to blow out the loose dust first. There's no sense spraying a lubricant on dirt and gumming things up worse.

[blearyeyes]

I like Chemtronics DPL (Deep Penetrating Lubricant). I've used it for years and it's always worked well for me. However, it's not readily available in most stores.
Deoxit is also a very good cleaner/lube.

Ive used Deoxit in the studio for years. Great for connections. I got some. I'll look for DPL while I'm out and about. Never thought to blow them out. Maybe I can blow out the Deoxit and the crud. 8-)

[blearyeyes]

I scooped out a little of the white stuff and it feels like really fine white grease. Ever heard of that being used in pots?

[blearyeyes]

some info to help you

Thanks for the schematics.

[The Dude]

Yes, there is grease in pots and faders on the "topside" mechanicals to make them move smoothly. This is one of the problems people have when they clean rotary pots and faders. They also clean away all of the grease by "flock shooting" them full of contact cleaner. It's important to know WHERE you want the contact cleaner inside the potentiometer. Generally speaking, there is a small circuit board on the backside that has traces. On top of that are the contacts. This is where you want the contact cleaner. You DO NOT want it elsewhere where it will dissolve the grease that makes it operate smoothly. A little goes a long way. This is more of a problem with faders than rotary pots, but the same applies. If you have an old pot or fader laying around, take it apart and study how it works. I've seen people completely ruin faders on mixers with cleaners and lubricants. Also, it's good to orient the pot with the wafer side towards the ground when cleaning. Gravity can be your friend.

[Enzo]

That is also why they make lubricating control cleaner.