Hello All
I came across this Eleven G a few weeks ago that basically just needed the pots clean. When running the balance and volume pots, they made noise and the speakers would cut in and out left and right while turning the balance. Both channels sounded fine though when testing at sellers place. I went through and cleaned the pots. I had to move around a few of the bottom boards not taking them all the way out, but just unscrewing them so I could get better access to the pots. Well pots now are smooth and accurate, however my left channel sounds a little distorted. Not horribly bad, but I can hear it. Right side is clear. I took out the jumpers and just ran the pre out to a small amp and left channel is fine, so it’s in the amp section. Could this be a grounding issue? The sound level between the channels is the same, left channel is not lower, just a little distorted when the bass kicks in. Any thoughts? Your input would greatly be appreciated.
I came across this Eleven G a few weeks ago that basically just needed the pots clean. When running the balance and volume pots, they made noise and the speakers would cut in and out left and right while turning the balance. Both channels sounded fine though when testing at sellers place. I went through and cleaned the pots. I had to move around a few of the bottom boards not taking them all the way out, but just unscrewing them so I could get better access to the pots. Well pots now are smooth and accurate, however my left channel sounds a little distorted. Not horribly bad, but I can hear it. Right side is clear. I took out the jumpers and just ran the pre out to a small amp and left channel is fine, so it’s in the amp section. Could this be a grounding issue? The sound level between the channels is the same, left channel is not lower, just a little distorted when the bass kicks in. Any thoughts? Your input would greatly be appreciated.
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Fill a syringe with iso propyl alcohol, and flush all the pots and switches.
That includes trimmers, measure before working those...
Work them while doing it.
After it is drained and dried, spray a contact cleaner.
Work them again.
Also remove the PCBs from the cabinet, clean and check the tracks too, for evidence of damage and previous repairs.
Leave it for a few hours, and see what happens.
If no improvement, then you will have to check the signal path, and find the possibly weak components.
Use the good channel as a reference.
That includes trimmers, measure before working those...
Work them while doing it.
After it is drained and dried, spray a contact cleaner.
Work them again.
Also remove the PCBs from the cabinet, clean and check the tracks too, for evidence of damage and previous repairs.
Leave it for a few hours, and see what happens.
If no improvement, then you will have to check the signal path, and find the possibly weak components.
Use the good channel as a reference.
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Thanks Naresh, I already went through the pots and switches with deoxit so it looks like the next step is the amplifier section. I ran just the pre out to a external amp and the left channel sounded just as good as the right. Think I should start with cleaning the relay up? Thought about checking for cracked solder connections too in the amp section.
You could use a dead bulb tester, and short out the relays to check.
Better to replace old relays, pitted contacts don't last after cleaning.
And the risk of damaging tracks during soldering is always there.
Re flowing the joints is a good idea, clean up extra flux with alcohol and old tooth brush...
Check all the capacitors, could be a silly (in retrospect) fault.
Better to replace old relays, pitted contacts don't last after cleaning.
And the risk of damaging tracks during soldering is always there.
Re flowing the joints is a good idea, clean up extra flux with alcohol and old tooth brush...
Check all the capacitors, could be a silly (in retrospect) fault.
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Common troubleshooting....
I use a signal tracer along the path from amp input to output.
Each stage gives a clue as to where the problem starts.
Then rectify the issue and enjoy the music.
I use a signal tracer along the path from amp input to output.
Each stage gives a clue as to where the problem starts.
Then rectify the issue and enjoy the music.
A silly solution : use a desktop computer speaker as the signal tracer, you will get to hear the sound as you progress through the circuit.
Just don't connect it to the outputs.
You can connect one input wire to a probe from a socket, and connect the other wire to ground. Only one channel is used.
I have used a tiny 2.5 inch speaker as the tracer.
Lovely old set, they just don't make this quality any more.
Nice to use when you get it working properly.
Just don't connect it to the outputs.
You can connect one input wire to a probe from a socket, and connect the other wire to ground. Only one channel is used.
I have used a tiny 2.5 inch speaker as the tracer.
Lovely old set, they just don't make this quality any more.
Nice to use when you get it working properly.
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Silly but effective nareshBrd I'll start with that.
This will be my first using a signal tracer wiseoldtech, guess I should see about purchasing one. Thanks to you both
This will be my first using a signal tracer wiseoldtech, guess I should see about purchasing one. Thanks to you both
It is a silly solution.
If you're going to be anything near a successful diy'er, you need to have and invest in the proper tools for the job.
Signal tracers are not expensive items, and have the requirements for troubleshooting an amplifer from input to output.
Why make things sloppy and difficult?
I repair about one amp in a year, so I don't really need one, this was a simple solution with readily available equipment.
I am still looking for an oscilloscope, I let an old one go, a new one is not worth it, too complex, all digital...that would be handy too.
I am still looking for an oscilloscope, I let an old one go, a new one is not worth it, too complex, all digital...that would be handy too.
Nice old kenwood, I like the acoustic compensator section before everyone later referred to it as a graphic eq.
we usually use faderlub on pots only. If something is distorted to hear it, you probably can see it on a scope using a sine wave. You can measure thd. You can check bias voltages
we usually use faderlub on pots only. If something is distorted to hear it, you probably can see it on a scope using a sine wave. You can measure thd. You can check bias voltages
I just want to say thanks to all you guys for your replies. I will be using some more deoxit and faderlub for the slides. I still have the speaker switches A B C, and the eq slides left to clean.
Believe it or not, it was one of my connectors on the power amp board was not fully seated. As soon as I fully seated that, turned it on, left channel was back to normal. I then proceeded to set the bias and then just listened. Believe that s*$#? I totally did not follow my own advice after doing computer work the last 20 years, “start with the simple stuff first”
I do have a Eleven II that will be up next that does have what seems to be a channel out from what I’m told. This one will be mine though so it will get the whole refurb process. But again, fix the issue first then proceed with the rest. I definitely want to get this signal tracing down pat.
Thanks a million guys!
Believe it or not, it was one of my connectors on the power amp board was not fully seated. As soon as I fully seated that, turned it on, left channel was back to normal. I then proceeded to set the bias and then just listened. Believe that s*$#? I totally did not follow my own advice after doing computer work the last 20 years, “start with the simple stuff first”
I do have a Eleven II that will be up next that does have what seems to be a channel out from what I’m told. This one will be mine though so it will get the whole refurb process. But again, fix the issue first then proceed with the rest. I definitely want to get this signal tracing down pat.
Thanks a million guys!
I take it then this set does not belong to you.
If you can, keep it with you until you finish fixing the next one, simply as a reference.
If you can, keep it with you until you finish fixing the next one, simply as a reference.