I JUST got this Sansui AU-11000 Fixed!
I connected a pair of Speakers [AR11's], and tested all the switches and adjustments on the front-panel to make sure everything was Good to Go.
I found everything to be Good. I noticed that the Balance was starting to feel funny. Figuring it was dirty, I turned it a few times from left to right.
And it got harder to turn.
I've never seen this happen to a Balance Control before.
I turned it a little more, thinking it would break-off anything that had built-up on it. And it started to feel as if there was Epoxy setting-up on it. :/
I removed the Bottom Panel, and checked it out. I appeared just fine.
I turned it just a little, and it didn't allow me to move it much anymore. This was weirding me out!!
I began to remove all the Switches and turn-knobs. I removed the entire Front-Panel. I found the ridiculous obstacle of a bracket, and figured out how to remove it, so I could clean the Balance Pot.
Well, it wasn't something you could just clean. It was entirely Internal.
I found that the Front-Bearing was locked-up. As if it was welded together or something.... I turned it back and forth using Pliers. It was actually tough to move, but I was careful not to damage it. Then ....
I decided to take apart the Pot. I did, and found it to move just fine.
The front-bearing the Culprit. I tried cleaning it, and even used some solvent on it. I didn't want to use WD-40 or anything, so I tried Rubbing Alcohol.
It didn't help break it free. I decided to put it back together, and try moving it with the Pliers again. It would barely budge. I got it to move a little more, and Gradually it started to move, it Installed back on the Bracket with the Wing-Nut holding it in place. I finally got it to Move Freely each direction.
I put the Front Panel back on, and the Balance Knob. I put the Power Knob on , connected the AR11's, and plugged in the AU-11000.
It powered-on just as it should. I turned-up the Volume, and heard sound from only the Left Channel. I Turned the Balance Knob, and the sound cut-out.
I turned it a little more each direction, and got the Right Channel working, but not the Left. I was upset, and knew the Balance Pot was toast.
I continued to adjust the Balance, and finally got Sound from Both Channels.
But all I had to do was turn it again, and it was back to square-one. 🙁
Now - I know this should be a Simple Part. It not easy to replace, since the Board has about 20 Wires soldered to it, and it doesn't look like I can remove the Board without Desolding all those wires. But I can do it.
The Question is, Where can I find a Replacement Balance Pot for a Sansui AU-11000?!? :O
This Amp is becoming a headache... First the Power-Transistors, and now THIS?!?
I connected a pair of Speakers [AR11's], and tested all the switches and adjustments on the front-panel to make sure everything was Good to Go.
I found everything to be Good. I noticed that the Balance was starting to feel funny. Figuring it was dirty, I turned it a few times from left to right.
And it got harder to turn.
I've never seen this happen to a Balance Control before.
I turned it a little more, thinking it would break-off anything that had built-up on it. And it started to feel as if there was Epoxy setting-up on it. :/
I removed the Bottom Panel, and checked it out. I appeared just fine.
I turned it just a little, and it didn't allow me to move it much anymore. This was weirding me out!!
I began to remove all the Switches and turn-knobs. I removed the entire Front-Panel. I found the ridiculous obstacle of a bracket, and figured out how to remove it, so I could clean the Balance Pot.
Well, it wasn't something you could just clean. It was entirely Internal.
I found that the Front-Bearing was locked-up. As if it was welded together or something.... I turned it back and forth using Pliers. It was actually tough to move, but I was careful not to damage it. Then ....
I decided to take apart the Pot. I did, and found it to move just fine.
The front-bearing the Culprit. I tried cleaning it, and even used some solvent on it. I didn't want to use WD-40 or anything, so I tried Rubbing Alcohol.
It didn't help break it free. I decided to put it back together, and try moving it with the Pliers again. It would barely budge. I got it to move a little more, and Gradually it started to move, it Installed back on the Bracket with the Wing-Nut holding it in place. I finally got it to Move Freely each direction.
I put the Front Panel back on, and the Balance Knob. I put the Power Knob on , connected the AR11's, and plugged in the AU-11000.
It powered-on just as it should. I turned-up the Volume, and heard sound from only the Left Channel. I Turned the Balance Knob, and the sound cut-out.
I turned it a little more each direction, and got the Right Channel working, but not the Left. I was upset, and knew the Balance Pot was toast.
I continued to adjust the Balance, and finally got Sound from Both Channels.
But all I had to do was turn it again, and it was back to square-one. 🙁
Now - I know this should be a Simple Part. It not easy to replace, since the Board has about 20 Wires soldered to it, and it doesn't look like I can remove the Board without Desolding all those wires. But I can do it.
The Question is, Where can I find a Replacement Balance Pot for a Sansui AU-11000?!? :O
This Amp is becoming a headache... First the Power-Transistors, and now THIS?!?
Ive only just noticed this post because Ive got a problem with my balance pot Diog! You dont have to take the faceplate off? You should used DeOxit to clean it! I use a diabetics syringe to get the DeOxit into the balance pot through those little hole on the top of each of the dual pots and give it about 20 full turns left to right to get it freed up properly.DeOxit is made for just this thing and works great. WD40 works great too but it wont last long and attracts dust and crap so that your worse off in the long run.You would be better off buying the big can of DeOxit from eBay instead of those piddling little expensive ones that last 5 minutes.
Thanks RedRooster, but I DID have to take off the Faceplate in this Situation...
The Issue, was that the Balance Pot totally Froze-Up. The Shaft felt like Super Glue has seized-up and dried. I used WD-40 with no luck. In fact, it froze up to the point where I had to use Pliers to move it, and it reached the point where it wouldn't even move with the Pliers. The Internal Parts were also seizing up as well.
I had to Replace the entire Balance Pot, which was a MAJOR PAIN because I couldn't find the Original. I ended up paying $25 for a USED Sansui 4000 Balance Pot, which was Long enough and was 250kΩ. I had to Drill Out the hole in the Plate it mounts to, because the Shaft with the Threads was Wider. I also have to clip-off ALL 6 Pins, and Soldier Wires in place, because the Pins weren't long enough. AND I had to Cut the Shaft, as it was a bit too long! And in the end, the Balance had an issue, where if you turned it all the way Left, it still had faint Audio coming from the Right Channel, which I found was not repairable. The Leads were not shorted at all, so it was another issue on some other board somewhere, no big deal...
I Believe the issue was that this Amp was in a rather Humid Environment not being used for a LONG Time!! Which when enough Water Vapor gets into the Shaft-Barrings, mixes with the Grease, the grease turns into Epoxy. Eventually, a few turns will mix the goo enough to Seize it completely.
The Prevention is Simple: Use PURE Lithium Grease on the Shaft-Bearings when they work PERFECTLY. And Do NOT Use Lithium Grease in a Can! That is actually an Oil/Grease Mix, which will Not last!! Lithium Grease in a TUBE is the RIGHT Stuff! 😉
Also - If it's an Old Amp like this Sansui was, then use a Drop of LUCAS OIL in the Bearing BEFORE you use Lithium Grease!!
I did just that to the replacement Sansui 4000 Balance Pot.
The Purpose of using Lithium Grease, is to SEAL it off, preventing water-vapors from getting inside. If it's old, it needs Lubed with something Similar to Lucas Oil, but ONLY a Drop! Lucas Oil is THICK and will not evaporate for years. But without Lithium Grease on top of that, water vapor can mix with that, and it can seize-up.
I think DeOxit would be Great, if I worked on enough Amps like this. But I do allot more work on Speakers and Computers. In fact, this past week I had to do Data Recovery on an external WD MyBook HDD. Data Recovery takes days, and in this case, the most valuable file was not recoverable. (The guy had a 138GB Image File, which is Insane!)
Big Files get lost first on Corrupt HDD's!!
WORD TO THE WISE--> LUBE it and SEAL your Pots, before they go to POT!! ;^)
The Issue, was that the Balance Pot totally Froze-Up. The Shaft felt like Super Glue has seized-up and dried. I used WD-40 with no luck. In fact, it froze up to the point where I had to use Pliers to move it, and it reached the point where it wouldn't even move with the Pliers. The Internal Parts were also seizing up as well.
I had to Replace the entire Balance Pot, which was a MAJOR PAIN because I couldn't find the Original. I ended up paying $25 for a USED Sansui 4000 Balance Pot, which was Long enough and was 250kΩ. I had to Drill Out the hole in the Plate it mounts to, because the Shaft with the Threads was Wider. I also have to clip-off ALL 6 Pins, and Soldier Wires in place, because the Pins weren't long enough. AND I had to Cut the Shaft, as it was a bit too long! And in the end, the Balance had an issue, where if you turned it all the way Left, it still had faint Audio coming from the Right Channel, which I found was not repairable. The Leads were not shorted at all, so it was another issue on some other board somewhere, no big deal...
I Believe the issue was that this Amp was in a rather Humid Environment not being used for a LONG Time!! Which when enough Water Vapor gets into the Shaft-Barrings, mixes with the Grease, the grease turns into Epoxy. Eventually, a few turns will mix the goo enough to Seize it completely.
The Prevention is Simple: Use PURE Lithium Grease on the Shaft-Bearings when they work PERFECTLY. And Do NOT Use Lithium Grease in a Can! That is actually an Oil/Grease Mix, which will Not last!! Lithium Grease in a TUBE is the RIGHT Stuff! 😉
Also - If it's an Old Amp like this Sansui was, then use a Drop of LUCAS OIL in the Bearing BEFORE you use Lithium Grease!!
I did just that to the replacement Sansui 4000 Balance Pot.
The Purpose of using Lithium Grease, is to SEAL it off, preventing water-vapors from getting inside. If it's old, it needs Lubed with something Similar to Lucas Oil, but ONLY a Drop! Lucas Oil is THICK and will not evaporate for years. But without Lithium Grease on top of that, water vapor can mix with that, and it can seize-up.
I think DeOxit would be Great, if I worked on enough Amps like this. But I do allot more work on Speakers and Computers. In fact, this past week I had to do Data Recovery on an external WD MyBook HDD. Data Recovery takes days, and in this case, the most valuable file was not recoverable. (The guy had a 138GB Image File, which is Insane!)
Big Files get lost first on Corrupt HDD's!!
WORD TO THE WISE--> LUBE it and SEAL your Pots, before they go to POT!! ;^)
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The Good News - I got everything Fixed, and back to the Customer!! :^)
It worked running COLD compared to what it was doing, and all with NO Distortion or Noise!
Before, it had some noise in both channels, more in the left.
I Guess when you replace over $200 worth of Parts in a Nice Vintage Amp, it's going to run Better than New! 😉
(Even though the Balance had a tiny flaw when turned all the way Left)
It worked running COLD compared to what it was doing, and all with NO Distortion or Noise!
Before, it had some noise in both channels, more in the left.
I Guess when you replace over $200 worth of Parts in a Nice Vintage Amp, it's going to run Better than New! 😉
(Even though the Balance had a tiny flaw when turned all the way Left)
It sounds more like someone has actually injected epoxy resin into the pot for some reason? Maybe to lock it in place? You shouldve taken some photos of the insides of the pot when you took it out.Anyway Im glad you got it fixed in the end mate! Thanks for posting about it because it all helps in the long run trying to work out what the hell is happening with these things? LOL😀
I think Dusty & Humidity mix together to lock these things up.
It actually worked fine for a few turns, and at some point it started to feel more difficult.
Replacing the Balance Pot with one that wasn't meant for this amp is like Surgery.
It actually worked fine for a few turns, and at some point it started to feel more difficult.
Replacing the Balance Pot with one that wasn't meant for this amp is like Surgery.
I wouldve waited until I had the right replacement.There always seems to be parts floating around on fleabay etc...I wonder if theres a way to re-coat the track with carbon? Maybe graphene mixed with some PVC wood glue,Im pretty sure that would work if the spline wasnt seized up. Graphene is very easy to make now days but I suppose it has to be applied in the right amount to get the right resistance?
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I looked for a couple of weeks. Nothing. And what makes it even more difficult to find, is the Length. It's 250kΩ Ballance Pot, with a rather Long Shaft and Long Pins.
I looked at allot of New 250kΩ Balance Pots, and the only ones that actually had the Shaft Length in the Description, were Pots that were too short. [Go figure]
I also searched for the Original Part. No one online, even Ebay didn't have a Sansui AU-11000 or AU-9900 Balance Pot.
I even looked up the Part Number written on the Pot. Nothing.
But, I found a Sansui 4000 Balance Pot, which was also 250kΩ with a Long Shaft.
It was a tiny bit wider, had a somewhat longer shaft, and shorter pins. But, with some modifications, it worked!
The only real complaint, besides the faint sound from the Right Speaker when panned all the way to the Left, is that the Nob doesn't fit it perfectly. It fits, but once you tighten-down the Screw, it turns just a tab Sideways. No biggie, still fits. But not like the original.
I always ask my Clients if they want to Proceed with New Parts. This was the only time when replacing parts really made me mad. But, these are Vintage Amps, and finding an Exact Replacement part is like playing the lottery.
I looked at allot of New 250kΩ Balance Pots, and the only ones that actually had the Shaft Length in the Description, were Pots that were too short. [Go figure]
I also searched for the Original Part. No one online, even Ebay didn't have a Sansui AU-11000 or AU-9900 Balance Pot.
I even looked up the Part Number written on the Pot. Nothing.
But, I found a Sansui 4000 Balance Pot, which was also 250kΩ with a Long Shaft.
It was a tiny bit wider, had a somewhat longer shaft, and shorter pins. But, with some modifications, it worked!
The only real complaint, besides the faint sound from the Right Speaker when panned all the way to the Left, is that the Nob doesn't fit it perfectly. It fits, but once you tighten-down the Screw, it turns just a tab Sideways. No biggie, still fits. But not like the original.
I always ask my Clients if they want to Proceed with New Parts. This was the only time when replacing parts really made me mad. But, these are Vintage Amps, and finding an Exact Replacement part is like playing the lottery.
It wouldve been relativly easy if you couldve swapped the original shaft into another 250k pot! The main thing is you got the amp going again and if the customers happy,its a good day!
Yes - That is True.
Though the Shaft was totally Seized inside the Potentiometer. It wasn't going to budge.
I just wish I didn't have to deal with it. Lots of work, and couldn't charge for the extra labor. And he had to settle for it. It's one of those Situations where he didn't think it was a Problem, but clearly it was going to happen eventually. Surprise, it happened in my hands while Testing the Amp after all the OTHER issues.
He WAS very Impressed with the non-existent noise/distortion. 😉
Though the Shaft was totally Seized inside the Potentiometer. It wasn't going to budge.
I just wish I didn't have to deal with it. Lots of work, and couldn't charge for the extra labor. And he had to settle for it. It's one of those Situations where he didn't think it was a Problem, but clearly it was going to happen eventually. Surprise, it happened in my hands while Testing the Amp after all the OTHER issues.
He WAS very Impressed with the non-existent noise/distortion. 😉
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