wireplusgain
New Member
Hi All,
Firstly, thanks to all those that have responded to similar posts, as I have learned so much in the last couple of weeks.
I have a Yamaha RX-V850 that I bought new in my teens and would dearly love to save it. It was retired from home theater duties many years ago but remained a beloved amp for music and never faltered. A change in living arrangements had it placed in storage in 2015, time flew by, and I have only now retrieved it and set it back up again.
It seemed fine at first, until several (very) loud cracks and pops came through the speakers and the unit shut down. Initially it powered back up, but did the same thing again after a brief period. I double/triple checked all my wiring, even swapping leads/cables out and changing the input source made no difference either. Even with the volume completely down, the cracks and pops would happen. Although fused, I changed to a cheaper set of bookshelf speakers for fear of damaging my good pair; that made no difference. The time also varied as to when it would do it and at its worst, the protection would shut it down immediately on start-up.
Following advice on this forum, I did the following:
Disconnected everything (inputs and speakers) but that made no difference. After varied amounts of time it would still shut down.
I noticed it was running warm/hot after first setting it back up. After reading about the individual channel idle adjustment, I checked the three channels (Left, Right, Rear) Left and Rear were about right (10mV?) but the Right channel was over 100mV, so I adjusted it down and it has run at a normal temp since.
I then did a DC leak test at the speaker terminals and was getting about 5mV, except for the Right channel, which appears to have now stabilized in the 30mV region. Initially it was jumping around, one time peaking over 100mV.
I have inspected the amplifier board with a magnifying glass and, to my eye, everything looks okay, but I am an absolute beginner at this. The capacitors all seem healthy looking (I've learned that is no guarantee) and I can't see any dry joints or anything untoward, except for a transistor(?) on the little board where the mains power comes in, close to the rear panel, where it has deposited a faint bit of soot.
I'm handy with a multimeter through troubleshooting vehicle electronics, but my experience with consumer electronics and PCB's is 'Beginner' level. I downloaded the service manual, have done a lot of reading online also, tried a few things (removed cleaned fuses, cleaned the Balance pot -which was scratchy- as well as the Volume, Bass, Treble) to no improvement. That said, the last 48 hours I have left it running and only came back twice to find it shut down in the first 24 hours. All of today it has run fine, although at a very low volume; an improvement of sorts.
Things don't fix themselves though, so given it's running relatively okay after getting nice and warm over two days, does that point to a particular area to focus on? Are there other tests I can do to troubleshoot this?
Firstly, thanks to all those that have responded to similar posts, as I have learned so much in the last couple of weeks.
I have a Yamaha RX-V850 that I bought new in my teens and would dearly love to save it. It was retired from home theater duties many years ago but remained a beloved amp for music and never faltered. A change in living arrangements had it placed in storage in 2015, time flew by, and I have only now retrieved it and set it back up again.
It seemed fine at first, until several (very) loud cracks and pops came through the speakers and the unit shut down. Initially it powered back up, but did the same thing again after a brief period. I double/triple checked all my wiring, even swapping leads/cables out and changing the input source made no difference either. Even with the volume completely down, the cracks and pops would happen. Although fused, I changed to a cheaper set of bookshelf speakers for fear of damaging my good pair; that made no difference. The time also varied as to when it would do it and at its worst, the protection would shut it down immediately on start-up.
Following advice on this forum, I did the following:
Disconnected everything (inputs and speakers) but that made no difference. After varied amounts of time it would still shut down.
I noticed it was running warm/hot after first setting it back up. After reading about the individual channel idle adjustment, I checked the three channels (Left, Right, Rear) Left and Rear were about right (10mV?) but the Right channel was over 100mV, so I adjusted it down and it has run at a normal temp since.
I then did a DC leak test at the speaker terminals and was getting about 5mV, except for the Right channel, which appears to have now stabilized in the 30mV region. Initially it was jumping around, one time peaking over 100mV.
I have inspected the amplifier board with a magnifying glass and, to my eye, everything looks okay, but I am an absolute beginner at this. The capacitors all seem healthy looking (I've learned that is no guarantee) and I can't see any dry joints or anything untoward, except for a transistor(?) on the little board where the mains power comes in, close to the rear panel, where it has deposited a faint bit of soot.
I'm handy with a multimeter through troubleshooting vehicle electronics, but my experience with consumer electronics and PCB's is 'Beginner' level. I downloaded the service manual, have done a lot of reading online also, tried a few things (removed cleaned fuses, cleaned the Balance pot -which was scratchy- as well as the Volume, Bass, Treble) to no improvement. That said, the last 48 hours I have left it running and only came back twice to find it shut down in the first 24 hours. All of today it has run fine, although at a very low volume; an improvement of sorts.
Things don't fix themselves though, so given it's running relatively okay after getting nice and warm over two days, does that point to a particular area to focus on? Are there other tests I can do to troubleshoot this?
