MiKR7200
New Member
Hey guys,
I picked up this KR-7200 a few weeks ago and have had intermittent right channel audio cut out ever since. It seemed like at first it was working longer before cutting out, and has starting occurring faster after power up lately. I have feverishly cleaned all pots especially volume/balance with deoxit, working the knobs a lot in between. I have cleaned the contacts numerous times on the speaker protection relay to no avail. I've tested dc offset which shows around 6.7mv left and 52mv right. I went through all the capacitors on the main amp board and replaced those that looked suspect (mostly 47uf and 220uf). The larger 220uf had an obvious leak so I was pretty excited that I had figured out the problem, yet just soldered them in and within 10 minutes of playing the right channel drops again. One thing I have figured out is that when the channel drops, if I turn off power, and turn it right back on its back on again, then a few minutes later the same thing again. Could it be a back relay? I've looked everywhere for cracked solder joints and cant see anything. It's getting frustrating at this point, but I know that I'm technically inclined, I have a service manual, I have tools, I'm just baffled and don't want to hand over $70 at the local shop for a bench test alone.
Any help would be greatly appreciated! Thanks!
Mike
I picked up this KR-7200 a few weeks ago and have had intermittent right channel audio cut out ever since. It seemed like at first it was working longer before cutting out, and has starting occurring faster after power up lately. I have feverishly cleaned all pots especially volume/balance with deoxit, working the knobs a lot in between. I have cleaned the contacts numerous times on the speaker protection relay to no avail. I've tested dc offset which shows around 6.7mv left and 52mv right. I went through all the capacitors on the main amp board and replaced those that looked suspect (mostly 47uf and 220uf). The larger 220uf had an obvious leak so I was pretty excited that I had figured out the problem, yet just soldered them in and within 10 minutes of playing the right channel drops again. One thing I have figured out is that when the channel drops, if I turn off power, and turn it right back on its back on again, then a few minutes later the same thing again. Could it be a back relay? I've looked everywhere for cracked solder joints and cant see anything. It's getting frustrating at this point, but I know that I'm technically inclined, I have a service manual, I have tools, I'm just baffled and don't want to hand over $70 at the local shop for a bench test alone.
Any help would be greatly appreciated! Thanks!
Mike