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Repairing vintage Pots

anthonywc

anthonywc

New Member
I recently got my hands on an old Sanyo DCX3300KA Quad Receiver. Went through and checked all electrical and replaced any bad caps. The problem I have is on the 4 individual volume pots and the master volume pot. The individual volume pots I can easily find online. But the Master volume pot is a 4 gang 250K with some odd hookups. Can these be rebuilt or is it just better to find another used one? Or do they make a newer style that is compatible with this?
 
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Welcome to AK.....Is the gang potentiometer broken or just dirty?
 
avionic said:
Welcome to AK.....Is the gang potentiometer broken or just dirty?
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So this is whats going on. My left rear channel plays slightly lower than the others and is scratchy when adjusting the master volume. As I get above 1/3 turn, it kicks in and is OK. Then I can use my individual volume controls to adjust sound. Tried DeOxy Fader and electrical cleaner. Helped a little but not perfect. Its not a killer but I would like to have complete volume control. Its similar to the quad pots used in the sansui QRX3000. I just think I have a dead spot in one gang and wonder if it can be a DIY repair or am I stuck using used parts??
 
century tek said:
I was gonna say, Deox! YUP! :thumbsup:

.........Or unless it somehow got dropped on its face or knobs. :dunno: :eek:
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I did not find any damage or bent shafts. If it was dropped the pots for the individual volume controls, bass, and treble are directly mount to boards. This would have shown some damage. Nothing seen. The master volume, however, is free floating and wires are soldered from it to the board. As I said early, I went through this thoroughly abd checked everything electrical. It all leads back to the master 4 gang pot.
 
Here is a few pics of the master volumecontrol and board its tied to. Looking at the side view: white wire is LR, then LF, then RF, and finally RR
 
deox first
i find most times operating pot in bad area a few times clears it up for a short while until i can be bothered sorting it with deoxit type stuff .
 
are the outside terminals all same resistance ? if so wiper is likely hitting some grit or dust and needs a good clean .
 
i would first flood it with cleaner then work it lots of times then give it plenty of time for it to dry out . the track appears good from what you say .so its a wiper issue not touching the track in a certain place for some reason
 
Finding a suitable replacement is not going to be easy. Unless a parts unit with a good control drops in your lap.
 
i have in the past swapped parts in pots but not with multiple ones like yours that look like pretty tricky to get back together in a working condition . not saying it cant be done but not for me .
 
petehall347 said:
i have in the past swapped parts in pots but not with multiple ones like yours that look like pretty tricky to get back together in a working condition . not saying it cant be done but not for me .
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I'm actually looking into this. Have found a few double gang 250K pots that may just work. I feel this may be a total rebuild. Either with new guts or total tear down of the pots and cleaning. Either way, it will be time consuming and tedious
 
Just an FYI, but I notice that the SM is calling out 200k pots. Also, even though all four gangs have the loudness tap, only the first two gangs actually have the "loudness" circuitry attached. The "rear" two only have a 47k resistor to ground. Not that that's helpful, but good luck with this project. It's always cool when someone can save an old rare unit like this.

Btw, do you actually use it as a 4-channel unit? Just curious.
 
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