I have a Proton 520 Stereo integrated amp which was working fine until recently, when one of the channels would begin sounding distorted. I found that wiggling the RCA input jacks would sometimes make it go away, but sometimes not. Swapping out RCA connect wires didn't make any changes, and neither did moving it to another input. On all inputs (Tuner, Video, DAD, Tape), it has the same problem. I opened up the unit and used a multimeter to test for continuity between the RCA jacks and the solder connections on the board, and found continuity on all connections. I guess that makes sense since there's some signal going through, but it's just not sounding clean.
Any suggestions on how to fix this? Should I just melt the solder on all the RCA connections, hoping that when it re-hardens, there's a better connection?
Thanks in advance.
Any suggestions on how to fix this? Should I just melt the solder on all the RCA connections, hoping that when it re-hardens, there's a better connection?
Thanks in advance.
Twingling components likely to be involved in this rca plug. Heating with a hair driyer, cooling if you have a spray can to do so. That' s about all there is to go at this kind of issue.
If moving connections to another input didn't make any difference, resoldering the sockets probably won't help either. It could be the ground connection, which is common to all inputs but it's also possible that there is a faulty component in the amplifier itself that is causing the problem, since the noise is common to all inputs .
This may have nothing to do with it, but pulling the thick wire pre-out/amplifier-in bridges and giving them a thorough clean is a good idea and eliminates another possibility that may have arisen with corrosion on the connectors. Another check to narrow down the possibilities... does the noise vary with adjusting the volume control?
This may have nothing to do with it, but pulling the thick wire pre-out/amplifier-in bridges and giving them a thorough clean is a good idea and eliminates another possibility that may have arisen with corrosion on the connectors. Another check to narrow down the possibilities... does the noise vary with adjusting the volume control?
Do you mean heating/cooling resistors/capacitors/transistors?
I do notice some discoloration around several resistors (see photo) near the inputs - could this have anything to do with it?
An externally hosted image should be here but it was not working when we last tested it.
Update: I tried plugging a source directly into the amp main in and it still is distorted in the L channel. So I guess that rules out the preamp section. Also I make the problem worse by wiggling the RCA jack on the L main in. It goes from distorted normal volume to distorted much quieter - like 20% volume. But I can't make it sound good by wiggling it.
Perhaps this is issue with the electronic components, in which case I'm over my head. Unless anyone has an idea, I may need to have a pro look at it.
Perhaps this is issue with the electronic components, in which case I'm over my head. Unless anyone has an idea, I may need to have a pro look at it.
Yes, this might locate a bad component or make it fail or locate a bad contact.
Have you looked at solder joints ? if dull, porous, it could be a dry joint, worth reheating with new solder. Switches are prone to bad contact, spray for this issue is worth trying.
VICTORY! I was about to resolder the main in jacks when I noticed that the solder connections had come loose around some of the main transistors. Since they're connected to an off-board heat sink, when the circuit board flexed, it worked the connections loose. I resoldered them and everything's like new. Thanks for the help, all!
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