Hey everyone new member here, I just discovered this forum while trying to find some information to fix a friends Kenwood KR-9600 and after some troubleshooting figured i'd make an account and give the forum a shot.
So this receiver had been sitting for quite awhile because of a popping noise in the speakers, I figured I take a look at it and found that after about 10 minutes the speakers would pop intermittently. So I changed the differential pairs and recapped both amp boards and the problem was solved. I also cleaned all the controls and connections with Deoxit as well. The receiver ran great for about a week while waiting for some led's for the tuner and meters to come in. Once I changed the lights and put it all back together I found the left channel was not working. So after some troubleshooting this is where im at.
I pulled out the light housing that holds all the lamps just to get it out of the way, obviously no change. So I have a 1kHz sine wave going in to the left and right AUX jack. I have signal going into the tone control board at pin 2 and coming out at the tone defeat pin 10 but not coming out at pin 4. So I disconnected the wire at pin 4 and probed the tone board at pin 4 and its working fine, but when you attach the wire which feeds the "push switch A board" I lose signal. So i'm thinking the problem is after the tone board in the "push switch A board" or further down the line. So I disconnected the output side of "push switch A board" at the volume control that feeds the amp boards and still no signal on pin 4 or any points on "push switch A board". I swapped the "push switch A board" output wires at the volume control and the left channel works great, so I know the amp stage is working. So to me it seems as though there is a short on the "push switch A board" for the left channel.
So that's where i'm at, i'm kinda stuck. Any help would be appreciated to try and solve this problem. I have a tone generator, multimeter, frequency counter with a probe, and a semiconductor analyzer for test equipment. I also have the service manual. Which I will post a link too as well. Thanks in advance to anyone willing to help. I appreciate it!
If you need anymore info please let me know.
Service Manual: https://audiocircuit.dk/downloads/kenwood/Kenwood-KR9400-rec-sm.pdf
So this receiver had been sitting for quite awhile because of a popping noise in the speakers, I figured I take a look at it and found that after about 10 minutes the speakers would pop intermittently. So I changed the differential pairs and recapped both amp boards and the problem was solved. I also cleaned all the controls and connections with Deoxit as well. The receiver ran great for about a week while waiting for some led's for the tuner and meters to come in. Once I changed the lights and put it all back together I found the left channel was not working. So after some troubleshooting this is where im at.
I pulled out the light housing that holds all the lamps just to get it out of the way, obviously no change. So I have a 1kHz sine wave going in to the left and right AUX jack. I have signal going into the tone control board at pin 2 and coming out at the tone defeat pin 10 but not coming out at pin 4. So I disconnected the wire at pin 4 and probed the tone board at pin 4 and its working fine, but when you attach the wire which feeds the "push switch A board" I lose signal. So i'm thinking the problem is after the tone board in the "push switch A board" or further down the line. So I disconnected the output side of "push switch A board" at the volume control that feeds the amp boards and still no signal on pin 4 or any points on "push switch A board". I swapped the "push switch A board" output wires at the volume control and the left channel works great, so I know the amp stage is working. So to me it seems as though there is a short on the "push switch A board" for the left channel.
So that's where i'm at, i'm kinda stuck. Any help would be appreciated to try and solve this problem. I have a tone generator, multimeter, frequency counter with a probe, and a semiconductor analyzer for test equipment. I also have the service manual. Which I will post a link too as well. Thanks in advance to anyone willing to help. I appreciate it!
If you need anymore info please let me know.
Service Manual: https://audiocircuit.dk/downloads/kenwood/Kenwood-KR9400-rec-sm.pdf
