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- Jul 21, 2019
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For what it's worth, my Marantz NR1608 was plagued by intermittent right channel headphone output, and here's some of the thought process I followed:
Did tapping on the chassis make a difference: Usually not
Power on/off: No real difference
Jiggle and unplug/re-plug headphones: No real difference.
Turn up volume higher: Worked, sometimes had to do this repeatedly, and then unit worked fine for remainder of listening session
Clearly there is a lot of relay action going on, as the unit senses when headphone is plugged in and relays are engaged. I disassembled the receiver so I could determine the exact parts being used (Hongfa Technology HF115F 012-2ZS4B). Figuring that some time would pass before the new parts would arrive, I reassembled the receiver, and surprise, the unit worked 100% for a couple of days! I had unplugged the CPU board and a number of interconnects but had otherwise made no changes, so this was "interesting".
On a hunch, I disassembled the receiver once again, but this time I treated the internal (Sn-plated) connections to some contact cleaner before reassembling. Worked great when reassembled, though headphone sensing started to become intermittent. So I squirted a little more contact cleaner into the (Ni-plated) headphone jack. That did the trick! I've experienced no further problems in the months since that time. Why shiny new internal connections in a late model receiver kept in a clean and dry environment should need cleaning, I have no idea.
As for the stock relays, Hongfa Technology is a new name to me, but manufacturer's specifications showed that Marantz had selected sealed units with AgNi contacts, which is exactly the sort of thing that I'd want to see for this application, so I'm glad that I did not waste $$ by replacing perfectly good parts. Your own situation may be different of course, but if no speakers had been connected to your amplifier's "B" terminals, there would have been no current flowing through that suspect relay, hence the contacts should not be pitted or worn. And even if oxidized, Ag is a good electrical conductor.
Did tapping on the chassis make a difference: Usually not
Power on/off: No real difference
Jiggle and unplug/re-plug headphones: No real difference.
Turn up volume higher: Worked, sometimes had to do this repeatedly, and then unit worked fine for remainder of listening session
Clearly there is a lot of relay action going on, as the unit senses when headphone is plugged in and relays are engaged. I disassembled the receiver so I could determine the exact parts being used (Hongfa Technology HF115F 012-2ZS4B). Figuring that some time would pass before the new parts would arrive, I reassembled the receiver, and surprise, the unit worked 100% for a couple of days! I had unplugged the CPU board and a number of interconnects but had otherwise made no changes, so this was "interesting".
On a hunch, I disassembled the receiver once again, but this time I treated the internal (Sn-plated) connections to some contact cleaner before reassembling. Worked great when reassembled, though headphone sensing started to become intermittent. So I squirted a little more contact cleaner into the (Ni-plated) headphone jack. That did the trick! I've experienced no further problems in the months since that time. Why shiny new internal connections in a late model receiver kept in a clean and dry environment should need cleaning, I have no idea.
As for the stock relays, Hongfa Technology is a new name to me, but manufacturer's specifications showed that Marantz had selected sealed units with AgNi contacts, which is exactly the sort of thing that I'd want to see for this application, so I'm glad that I did not waste $$ by replacing perfectly good parts. Your own situation may be different of course, but if no speakers had been connected to your amplifier's "B" terminals, there would have been no current flowing through that suspect relay, hence the contacts should not be pitted or worn. And even if oxidized, Ag is a good electrical conductor.