Kenwood KR-6600 no sound on one channel

[Gbtr6]

I’m starting to work on a pretty clean KR-6600. It has sound only on the one channel. I am cleaning all the switches and filter switches. As some of 6pm know, the switches are hard to get at. If the channel doesn’t come back from cleaning like many do, what can I check first? I have a DMM, also have an oscilloscope. Have not used it and quite frankly don’t know how. Need to learn.

Thank you,
Perry

 

[Semanon]

Do you have a service manual? This will be helpful.

Even though it's not likely a power supply issue, I like to test the power supply voltages when I open up a unit. It's a good general health check.

After you clean the switches, the next suspect is the relay. These can get very dirty. Start by tapping it to see if you get any sound or static. You can do a temporary clean it by removing the clear plastic cover (with power off) and running a piece of paper soaked in Deoxit through the contacts until it until the paper comes through clean. If this works, consider replacing the relay. It will become a problem again in short time.

Once you have done a good job on switch/knob cleaning and done the relay, you will need to trace the signal through the unit to find where it stops. This is where the service manual comes in handy.

 

[Gbtr6]

I do have theservice manual. I'm getting back to this unit now. Will try cleaning again first.

Perry

 

[rickl]

I checked my notes and my last kr-6600 was in 2023.

I'd determine which channel is not working and try to fix it.

if you need help determining which channel is bad, look at power supply "c". a simple dvm should be fine.

please post your results or questions.

 

[Gbtr6]

Tried cleaning again. I have both channels but one is either too loud or the other is too low. What could cause that?

Thanks,
Perry

 

[gort69]

If the “ SOUND INJECT” knob is pulled out push it back in. That pot gets frequently neglected, and dirty due to the fact that probably no one ever uses it.

 

[Gbtr6]

I cleaned the sound inject switch and pot. I don’t think it’s working because on my other units with it, it reduces volume of the source as you turn the knob clockwise. This one does not seem to have any effect.

Perry

 

[Gbtr6]

I think the one channel is louder than the other. The ‘softer’ channel performs the same as my 7600. I am cleaning the volume pot again. What else might cause that?

Perry

 

[rickl]

Don't forget balance pot too.

 

[Gbtr6]

I’ve tried to clean the volume pot, balance pot, and sound injection. No luck. The sound protect circuit is slow too. May leave this one sit a bit. I’ve got a 7600 that doesn’t come out of protection.

Perry

 

[Semanon]

The sound protect circuit is slow too.

The first stop for fixing this are the capacitors asspciated with the relay and the resto of the protection circuit followed by the transistors.

Did you check/clean the relay? It's a pretty easy thing and dirty contacts have caused the exact symptoms you describe in units I have owned.