Kenwood Basic c2 balance adjustment pot
- Thread starter purenrg
- Start date
Yeah, no worries. I did have trouble, sadly it was at the very end of fiddling around with that pot, wish I'd broken it at the start and not the end!!
I deoxited the whole thing the other day and all my other troubles are gone (intermittent crackles, one channel dropping out after a couple of hours of play).
I deoxited the whole thing the other day and all my other troubles are gone (intermittent crackles, one channel dropping out after a couple of hours of play).
amb426amb1
New Member
Not an expert in this area but just went thru adjusting my Sansui integrated and brought everything back into specs and it is running noticeably cooler. The bias had shifted up. I also have the C2 pre with a bad balance pot. I'm going for the bi-pass fix. I don't recall it ever running very warm. I'll try to get it out of storage fix the balance and play it to test how warm it gets.
amb426amb1
New Member
Ok I did the balance fix this morning and ran the unit for about 3 hours straight. It did not get very warm at all. If you feel that much heat i would start checking things out.
Good Lord! You're joking, right? You live in LA, and can't track down a proper resistor?
Nope. I couldn't, not in Rat shack, not in Frys, not anywhere close to me, I went in about 5 different stores... I could have got one off the web but I figured this would work and it did. Not pretty though, if you're not impatient like me order one off the web.
petehall347
the brandy coffee man
just a thought if you get the correct resistors mount them on top of the board for a neater job .
failing that put a new balance pot in there .
or even leave the old pot in place and add the shorts .:scratch2:
failing that put a new balance pot in there .
or even leave the old pot in place and add the shorts .:scratch2:
can anybody explain why the resistors are needed? I bypassed mine with 2 jumpers as described in some of the other threads and it works fine.
Looks like so, the two jumpers at VR-1 on the board:
https://twitter.com/realsteveeboy/status/327051242851426305/photo/1
When I removed the balance pot, I tested it with a DMM and found that in the center position the resistance was "0" anyway. At each end(right or left) the resistance was exactly the same, but cannot recall the value right now. but 99.9% sure it wasn't 180k ohm or anything.)
This is because my pot was actually NOT not bad at all, NOT the problem. My issue with the channel going out turned out to be the tape/source monitor switch. I cleaned that out more thoroughly and now the unit seems to work fine with the bypass installed and no pot in place. Some of the other threads on the C2 note that before you do anything, you need to check that switch and clean it out real well.
DUH!
Yes, I am a dumb ass. Should have tested first, de-soldered later! Would have saved some hassles for sure.
So, back to the original question, are the 180k ohm resistors necessary?
If so, why?
I will probably re-install the pot when I get a chance, but kind of sick or working on it right now and just want to enjoy the unit for a while.
Another fix I had to perform was on two of the source inputs (tuner and aux 1). Back in college I lived in a house with some really sketchy knob and tube wiring. On two occasions I blew out inputs when I attempted to plug in some PA outputs to my C2 when those items were plugged into a different outlet. Heard a lour POP! Saw an arc at the RCA jack, and then the input went dead.
As part of this general attempt to fix the C2 I finally disassembled the boards, flipped them over, and found these two burnt traces for aux 1 and tuner inputs:
https://twitter.com/realsteveeboy/status/327053337142890496/photo/1
This thing is very easy to work on, even for a noob like me, so I figured I could jumper that real easily. I think the euro units have a couple of caps on the inputs which are not present on my universal unit, so I de-soldered the filled holes for those caps for each input... Like so (note open holes):
https://twitter.com/realsteveeboy/status/327054530690809856/photo/1
Then I realized at this point I was going to jump to a pad feeding another jumper, so I could just go all the way to that jumper's end point near the switch. So, I removed J46 and J48 and went from that empty input cap pad to the removed jumper pads. Like so:
https://twitter.com/realsteveeboy/status/327055154807451648/photo/1
So, the fiasco of removing and jumpering the still working balance pot was at least a bit tempered by the fact that now my aux 1 and tuner inputs work for the first time since @1993.
I really appreciate all the info and expertise on here, it's a great help to those dumb enough to crack these units open and attempt repairs.
Looks like so, the two jumpers at VR-1 on the board:
https://twitter.com/realsteveeboy/status/327051242851426305/photo/1
When I removed the balance pot, I tested it with a DMM and found that in the center position the resistance was "0" anyway. At each end(right or left) the resistance was exactly the same, but cannot recall the value right now. but 99.9% sure it wasn't 180k ohm or anything.)
This is because my pot was actually NOT not bad at all, NOT the problem. My issue with the channel going out turned out to be the tape/source monitor switch. I cleaned that out more thoroughly and now the unit seems to work fine with the bypass installed and no pot in place. Some of the other threads on the C2 note that before you do anything, you need to check that switch and clean it out real well.
DUH!
Yes, I am a dumb ass. Should have tested first, de-soldered later! Would have saved some hassles for sure.
So, back to the original question, are the 180k ohm resistors necessary?
If so, why?
I will probably re-install the pot when I get a chance, but kind of sick or working on it right now and just want to enjoy the unit for a while.
Another fix I had to perform was on two of the source inputs (tuner and aux 1). Back in college I lived in a house with some really sketchy knob and tube wiring. On two occasions I blew out inputs when I attempted to plug in some PA outputs to my C2 when those items were plugged into a different outlet. Heard a lour POP! Saw an arc at the RCA jack, and then the input went dead.
As part of this general attempt to fix the C2 I finally disassembled the boards, flipped them over, and found these two burnt traces for aux 1 and tuner inputs:
https://twitter.com/realsteveeboy/status/327053337142890496/photo/1
This thing is very easy to work on, even for a noob like me, so I figured I could jumper that real easily. I think the euro units have a couple of caps on the inputs which are not present on my universal unit, so I de-soldered the filled holes for those caps for each input... Like so (note open holes):
https://twitter.com/realsteveeboy/status/327054530690809856/photo/1
Then I realized at this point I was going to jump to a pad feeding another jumper, so I could just go all the way to that jumper's end point near the switch. So, I removed J46 and J48 and went from that empty input cap pad to the removed jumper pads. Like so:
https://twitter.com/realsteveeboy/status/327055154807451648/photo/1
So, the fiasco of removing and jumpering the still working balance pot was at least a bit tempered by the fact that now my aux 1 and tuner inputs work for the first time since @1993.
I really appreciate all the info and expertise on here, it's a great help to those dumb enough to crack these units open and attempt repairs.
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dannomite123
New Member
Hey all. New to the forum and glad to see its full of so many knowledgeable folks.
My problem started off the same. Dodgy balance pot. It was quite scratchy to operate and sometimes you would get a terrible distorted sound out of the blue.
I sprayed it with Deoxit to no avail. So I pulled it apart and noticed no real contamination or oxidization. I pulled the swipers out a bit thinking they had lost tension and were not making good contact with the rings. What I didnt notice was the left channel swiper had come away from the plastic, broken rivets.
I placed it back it and powered up the unit and noticed the left channel was completely dead. I pulled the balance pot apart again this time noticing the left channel swiper completely detached from the plastic. I glued it back on, reassembled and checked with multimeter. It all checked fine. Soldered it back in but still no left channel.
I hooked my oscilloscope(limited experience with this...) with a 500Hz sine wave from the function generator. Probing from the input jacks from inside the C2 I found the right channel was spot on but the left channel was only displaying a signal half the strength. I traced the left channel signal which displayed the same weakness to a 330 ohm resistor just before the balance pot and it died straight after the resistor. The resistor tested fine but I think its irrelevant as the signal was already weak.
I tried with all the inputs on the back with the same results. Weak left channel signal. I swapped the rca leads from the function generator with no luck and hooked the C2 to my power amp and speakers and left channel is definitely dead.
I know scopes are supposed to help you trace where a signal goes bad, but how do you do that when its already bad at the source? My only guess is that something got shorted when I reinstalled the balance pot the first time with the loose swiper.
I apologise for my long winded explanation in advance.
My problem started off the same. Dodgy balance pot. It was quite scratchy to operate and sometimes you would get a terrible distorted sound out of the blue.
I sprayed it with Deoxit to no avail. So I pulled it apart and noticed no real contamination or oxidization. I pulled the swipers out a bit thinking they had lost tension and were not making good contact with the rings. What I didnt notice was the left channel swiper had come away from the plastic, broken rivets.
I placed it back it and powered up the unit and noticed the left channel was completely dead. I pulled the balance pot apart again this time noticing the left channel swiper completely detached from the plastic. I glued it back on, reassembled and checked with multimeter. It all checked fine. Soldered it back in but still no left channel.
I hooked my oscilloscope(limited experience with this...) with a 500Hz sine wave from the function generator. Probing from the input jacks from inside the C2 I found the right channel was spot on but the left channel was only displaying a signal half the strength. I traced the left channel signal which displayed the same weakness to a 330 ohm resistor just before the balance pot and it died straight after the resistor. The resistor tested fine but I think its irrelevant as the signal was already weak.
I tried with all the inputs on the back with the same results. Weak left channel signal. I swapped the rca leads from the function generator with no luck and hooked the C2 to my power amp and speakers and left channel is definitely dead.
I know scopes are supposed to help you trace where a signal goes bad, but how do you do that when its already bad at the source? My only guess is that something got shorted when I reinstalled the balance pot the first time with the loose swiper.
I apologise for my long winded explanation in advance.
I have a Kenwood pre amp C1 and one channel is always quieter as the other. So i must adjust the balance control to +2 so that it gets reasonable result though the good channel seem to be more clearly, strongerly (bass & treble).
Suspecting the balance volume should be the culpit i have sprayed CRC -2-26, severaltime but with no result.
Trying bypass with 2 resitors 180K as someone stated in a german website about but further no result.
As my last trial before i will bring it to a service center i try to relace the volume pot. (alps dual gang 100kaX2 but only with 3 legs) and the wonder both channels now absolutely equally.
So the culpit is the volume pot, not the balance in my KENWOOD C1.
Now i can use it without problem. Of course i must forget the loudness function because i can not find a alps dual gang 100Kx2 with 4 legs(4. leg is intended for loudness). but i can accept it since i never use loudness.
janikphoto
Lunatic Member
So, does anyone have pics from those who just used jumpers? Is it done exactly the same as the resistors... just with jumper wire instead?
janikphoto
Lunatic Member
OK, I jumped it, but now I get NO sound. I'm moving backwards here... I left the pot in. Do I need to remove it to make this work, or can I leave it and this bypass will work?
*****UPDATE*****
So, I went back and snipped the jumpers, just to see if adding the resistors would make a difference. They are still there, just clipped in the middle and the mini solder jumps in place, too. I powered it up, just to see what would happen with them clipped and before the resistors went in. It plays now! Full stereo sound with no balance adjustment. So, at least I'm working now! Sound is superb through headphones, so I'm guessing you might not need the resistors, just do the solder jumps on their own.
*****UPDATE*****
So, I went back and snipped the jumpers, just to see if adding the resistors would make a difference. They are still there, just clipped in the middle and the mini solder jumps in place, too. I powered it up, just to see what would happen with them clipped and before the resistors went in. It plays now! Full stereo sound with no balance adjustment. So, at least I'm working now! Sound is superb through headphones, so I'm guessing you might not need the resistors, just do the solder jumps on their own.
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Well, you can't jumper them ALL together...one of those pads is ground.
janikphoto
Lunatic Member
Well, you can't jumper them ALL together...one of those pads is ground.
So, the resistor is just there to go from positive to ground, and when I used a solid wire, it was shorting it. I'm guessing, anyway. Either way, it's working now!
