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Yamaha CR-820 cleaning input select switch and mute button

N

nanderson

New Member
I have a CR-820 that I picked up a few weeks ago. I've since replaced the lamps and sprayed the pots with Deoxit/Faderlube.

Today I noticed that the Input select switch seems to be dirty, left channel intermittently cuts out on AUX. In the past the mute button has also seemed to stick on one channel. What is the right way to clean these two parts? Can I just spray at them or is there a specific part I should aim for or avoid? Is faderlube or deoxit better for these two parts?

Another small issue I noticed is that adding an antenna (read: speaker wire) doesn't seem to increase my signal Q but that may have to wait for another post unless there's a common issue in the tuner that someone can point out. I have a Kenwood tuner that shows a clear difference with the antenna connected vs not but I can't get the same on the Yamaha.
 
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At a glance disassembly of these switches looks like a pretty involved process: lots of desoldering, maybe removing the faceplate to take out the front panel assembly?

Can I hit maybe 90% without taking them fully apart? I think I'd sooner deal with a little bit of oxidation then do disassembly this weekend. Are there any pictures of the slide switches disassembled? It's tough to tell through the metal shield where the contacts actually lie.
 
nanderson said:
Can I hit maybe 90% without taking them fully apart? I
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More like less than 10%..Once you get one disassembled you will see why. The actual sliders reside within a plastic pocket. Shielding them from any chance of getting enough deox-it on them to do any good.
 
Switch will look similar to this. Guarantee it will be just as blackened as this one is.

Before...
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After....


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I used a polymer drafting eraser to clean off the majority of the oxidation/tarnish ..Then give it a light coat of D100 before reassembly.

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Oh that is pretty substantial. That looks like something I'll need to do but I may kick the can down the road until I have a list of a few more things that need to be serviced on it.

Do you have any thoughts on the tuner issue I mentioned?
 
As far as the -20 db button issue, you may wish to check all of the soldiered connections on the -20db PCB, especially the audio cable that goes back to the Volume/Balance PCB. Some of those could need re-flowed too.
 
Tuner alignment may need some tweeking.. I don't do tuner alignments online. I suggest you do the same unless you have the test equipment and knowledge.
 
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