Source Selector Fix-It Tips


The brother has an old Yamaha receiver that is having trouble with the source selector knob. When you move it, and sometimes when you don't, the channels fizzle in and out. You can usually fiddle with it long enough to dial them both in, but it's spotty and annoying as all get out. Now, I'm hoping that the thing is just dirty (it's about 12 years old) and that I'll be able to go in and clean it up. While I'm more than happy to wing it, I though to ask for a few pointers first. Should I be thinking about disassembling the thing and cleaning it, or would a good cleaning / lubrication do the trick? Would you want to put oil, grease or some other "wet" lubricant/cleaning agent on this sort of stuff, or is it best kept dry with graphite or the like? It may very well be busted and need more than cleaning, but I figure I should try this first. Any pointers would be much appreciated. Many thanks.
mezmo
The selector switch can be cleaned with a dry solvent spray product: Electrowash from Newark Electronics is my favorite but there are many others. Check on mcmelectronics.com Some contact cleaners contain an oil lubricant but try to avoid them if possible; the oil attracts dust & dirt right back into the contact area. Some old rotary TV tuners needed a lubricant to rotate smoothly so that's where this idea originated & in that application it is a good idea. Anyway just spray into the control & them rotate it several times to clear out the dust; repeat as required. Works on noisy pots too.
The guy that just got done calibrating my $15,000 signal generator said that the best cleaner / lubricant that he has ever used can be found at Radio Shack !!! This guy services and calibrates hospital gear, TV & FM broadcast stations, etc.. and has been doing so for 20+ years.

The solvent that he's referring to is their TV tuner cleaner / lubricant. Don't buy the "color" TV tuner / lubricant spray that costs more, as the only difference is that it is scented. He has used it in "sealed" controls over 12 years ago and it is still "liquid" and not all "gunked" up. Then again, ANY cleaner / lubricant will get nasty if you have it in an extremely dirty / dusty environment. I'm sure that someone makes this for Rat Shack, but we don't know what manufacturer or product name that it is directly marketed under.

My experience with this cleaner is that it worked well and i've never had a problem with it. Since i use a LOT of solvent at work, it was simply too expensive to use all the time. I prefer the Rat Shack stuff to the highly respected and widely used ( by technicians ) "Blue Shower" foaming cleaner / lubricant any day.

The stuff that Bob mentioned ( Electrowash ) is quite good for initially flushing controls out. However, if you do rotate the control quite a bit or it has metal to metal contacts that can pit, a bit of lubricant can be a good thing.

Here's a link to something that might help you or some others better understand how to clean a control or switch. At the time of this post, i had not used the Rat Shack stuff. Shortly after that, we ran out at work and i had to pick up some "emergency" supplies. The Rat Shack stuff worked MUCH better than expected and i wouldn't hesitate to recommend it. Just keep in mind that it IS lubricated and follow the guidelines that i mention in the post below. Sean
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http://www.audioasylum.com/audio/general/messages/64237.html

Radio Shack used to offer more than one kind of 'tv tuner cleaner'. The labeling on the cans tells you how much residue it leaves behind. It works great but some units seem to find it addictive.
Just to follow up, gave the item in question a good dousing (or six) with the Rat Shack TV tuner cleaner/lubricant as advised, and it worked like a charm. Only time will tell how long it takes, but, in the meantime, my brother (who has got to be one of the most mechanically and electronically disinclined individuals on god's green earth) thinks I'm a damned wizard. Good stuff, thanks again.