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I picked up a vintage Pioneer SX-626 receiver last night on kijiji. It was in decent shape and a very good price, but it needed a good cleaning because the owner was a smoker. When I hooked it up, it got a lot of FM stations, even with just a length of speaker wire for an antenna, but the controls were scratchy so I cleaned them with NuTrol.
I also thought that it would be a good idea to spray the tuner ... but that turned out to be a bad idea. Now it hardly picks up any stations at all. Is there anything that I can do to fix it? Would I be expecting too much for it to sort itself out in time? I realize that this was entirely self-inflicted, but any advice is appreciated. Thanks.
Prehistoric 4-Channel Lizard
Follow Ups:
Hi Quadzilla,
When you say that you "Sprayed the tuner" I'm guessing that you mean the tuning cap fins. Not being sure what all is in NuTrol but cleaners & lubricants are probably in the mix which when deposited on the fins of the tuning capacitor have changed the alignment and capacitance of each gang.
In order to recover from this you need to dissolve/dilute/remove ANY residue from the fins and leave nothing behind to contaminate the fins.
This is all a matter of degree so try a sequence of solvents, maybe start with something like a non residue tuner cleaner, acetone (being careful around flame and plastics, alcohol, and stuff like that. I've even used automotive "Brake Cleaner") to strip away any oils(again being careful).
In the end you want "nothing" or as little as possible left on the fins.
Remember after all this aggressive cleaning that there are 2 bearing points at either end of the shaft that DOES require lubricant and there are the interstage contact springs from the frame to the center shaft that benefit from a small amount of cleaner/lubricant like Caigs De-oxit D5 to maintain contact.
There is a lengthy discussion regarding this exact issue over in the Yahoo FM Tuner Group, message number 68309, but in the end you want the fins clean with no residue and any contact/bearing points lubricated.
Hope this helps.
HA
Thank you Hoosier, that helps a lot. I thought it might get better as things dried out, but it isn't any better today. I appreciate the help.
Prehistoric 4-Channel Lizard
Quadzilla, next thyme try CRC's QD Contact Cleaner for cleaning variable capacitor fins. Available at most hardware stores. Got that tip from AK. 73s para Sactown!!!
Great tip FRG7SWL! The hardware store a few blocks away had two cans in stock. I sprayed the fins once, and it started to come back. I gave it another spray about an hour later, and it looks like it is back to the way it was when I bought it. Thanks a bunch for the advice. I really appreciate it.
Prehistoric 4-Channel Lizard
Edits: 05/13/12
The responses are correct. Spraying cleaners that include oils and/or greases are almost always going to change the tuning of the 100mHz front end tuning capacitor and related fixed capacitors and nearby parts. The dielectric insulation between the tuning capacitor fins is supposed to be air, not some other material. Contaminants of various types can and do change the tuning of the circuits.
Some solvents can be damaging to various plastics and paints/inks used on circuit boards. I would experiment with a small amount on a Q-tip first to make sure it is not going to dissolve the component identifiers on the board or destroy a stryene capacitor etc. on the circuit board. Once you are confident that the solvend is not going to create other problems with circuitry, be watchful of how you orient the chassis to spray the cleaning solvent onto the front end parts. It usually is best to make sure any drips cannot fall onto the front panel or dial area. Those often have plastics that can be damaged by various solvents. You can also fabricate a paper shield and place it such that any overspray is kept away from anything you think might be sensitive to the solvent.
As some noted, the pivot points of the tuning capacitor shaft do need lubrication. Sometimes the old lubrication dries out and has to be cleaned out and then renewed. Do that with suitable solvent and then do not turn the capacitor until you have put new lubrication on the bearing surfaces. Some of these have a ball-bearing drive, so don't attempt to take one apart or you may have a real problem on your hands.
Once the contaminating oils and/or grease are removed from the front end and it has had sufficient drying time the tuning should return to normal.
Good luck!
Joe
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