Hi all,
I've been lurking on these boards for a while, and I'm just amazed at all of the great knowledge on this board. I was hoping a few of you might chime in and offer some advice and insight.
About a year and a half ago I picked up a KR-7600. It seemed to be in pretty good condition, and it played great for a few months before I began to have problems with the right channel.
Once the receiver gets warmed up, the right channel will cut out. It doesn't cut out completely but the volume drops to a very low level, while the left channel continues to play normally. The drop out (drop down?) happens after it has been playing for 20-40 minutes, though I've had it play normally for as long as four hours before the problem recurs. It happens on all inputs, including the radio.
The interior is pretty clean. I sprayed deoxit in all of the pots, and I replaced some obviously damaged caps in the power supply and amp board. I'm planning to replace the power filter caps as well, and frankly the whole thing could probably stand to be recapped. I saw some minor carbon build up, and a lot of the solder joints should probably be retouched as well.
I'm admittedly a noob, but I have slightly more time than money on my hands. I'd like to be able to fix what I can on my own and use this as a learning opportunity.
I talked to a tech about it a while back, and he thought that it might be a damaged transistor somewhere in the power supply or amp board that had failed or was close to failing and that it was going into protection mode once things heated up. Does that sound plausible? If it is a bad transistor, what's the best way to go about finding and replacing it?
For now, I'm planning to recap the power supply and amp board (because it probably needs doing anyway). There are also a pair of damaged (leaking brown goo) caps on the control board that I'll replace. I'll also retouch any solder joints that need it. Then I'll... start pulling transistors on the amp board and testing them?
I'd really appreciate any advice you can offer, especially if you're familiar with this model. Any other theories or possible solutions are welcome. I can post some pics later. Thanks for your help!
I've been lurking on these boards for a while, and I'm just amazed at all of the great knowledge on this board. I was hoping a few of you might chime in and offer some advice and insight.
About a year and a half ago I picked up a KR-7600. It seemed to be in pretty good condition, and it played great for a few months before I began to have problems with the right channel.
Once the receiver gets warmed up, the right channel will cut out. It doesn't cut out completely but the volume drops to a very low level, while the left channel continues to play normally. The drop out (drop down?) happens after it has been playing for 20-40 minutes, though I've had it play normally for as long as four hours before the problem recurs. It happens on all inputs, including the radio.
The interior is pretty clean. I sprayed deoxit in all of the pots, and I replaced some obviously damaged caps in the power supply and amp board. I'm planning to replace the power filter caps as well, and frankly the whole thing could probably stand to be recapped. I saw some minor carbon build up, and a lot of the solder joints should probably be retouched as well.
I'm admittedly a noob, but I have slightly more time than money on my hands. I'd like to be able to fix what I can on my own and use this as a learning opportunity.
I talked to a tech about it a while back, and he thought that it might be a damaged transistor somewhere in the power supply or amp board that had failed or was close to failing and that it was going into protection mode once things heated up. Does that sound plausible? If it is a bad transistor, what's the best way to go about finding and replacing it?
For now, I'm planning to recap the power supply and amp board (because it probably needs doing anyway). There are also a pair of damaged (leaking brown goo) caps on the control board that I'll replace. I'll also retouch any solder joints that need it. Then I'll... start pulling transistors on the amp board and testing them?
I'd really appreciate any advice you can offer, especially if you're familiar with this model. Any other theories or possible solutions are welcome. I can post some pics later. Thanks for your help!