I have a 30yo Rotel RC-850 preamp that intermittently and briefly experiences decreased volume in one channel after an hour or so of operation.
I was able to find a schematic online.
Does this behavior description point to a common cause or am I faced with swapping parts until it goes away?
I was able to find a schematic online.
Does this behavior description point to a common cause or am I faced with swapping parts until it goes away?
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Don't swap parts (that's likely to damage the board), signal trace instead.
That should be especially easy on this board. Most likely to be a bad connection or solder joint.
Could be the output muting relay RY901, check that.
That should be especially easy on this board. Most likely to be a bad connection or solder joint.
Could be the output muting relay RY901, check that.
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I would poke with a chop-stick. Some techs try Freeze-Spray to induce intermitents. As said, random swap is liable to increase troubles.
Instead of "swap" I should have used "replace."
It's been a couple months but I don't believe the output cuts out completely and with a single for both channels, I would expect a relay to cause muting.
I'll try chopstick and freeze spray as well as flip the board for inspection.
I've had it since new and it only began exhibiting the issue this year. It's been used sporadically the last 15 years.
It's been a couple months but I don't believe the output cuts out completely and with a single for both channels, I would expect a relay to cause muting.
I'll try chopstick and freeze spray as well as flip the board for inspection.
I've had it since new and it only began exhibiting the issue this year. It's been used sporadically the last 15 years.
I would rule out the relay first, it's the most likely culprit in this case.
Just replacing parts is never a good approach. A little knowledge can go a long way.
Just replacing parts is never a good approach. A little knowledge can go a long way.
Start with the basics:
Deoxit pots & switches.
Check for bad solder pads.
Check the relay contacts.
When it happens, tap the board / trace the signal. It's easy to follow on this board.
Deoxit pots & switches.
Check for bad solder pads.
Check the relay contacts.
When it happens, tap the board / trace the signal. It's easy to follow on this board.
You can signal trace with a small active computer speaker MacGyvered with a VOM probe.
I agree with above advice about the relay. Look at this thread. Small Signal Relay Oxidation Problems
I agree with above advice about the relay. Look at this thread. Small Signal Relay Oxidation Problems