JVC receiver one channel fades out in headphones

J

JvcCap

New Member
Hi,

I have a JVC RX-884RBK unit and the problem is that when I switch it on the first time and plug in headphones, one channel might be breaking in and out. There is kind of a scratchy distortion going on during that moment. As if a connection is bad somewhere. It eventually comes back after some time, but still sounds maybe a tiny bit weaker than the other one. It doesn't fade in the regular speakers, however I still feel a bit of 'weaker' sound through it. I've tested it from different inputs and sources, it's the same in every one. Same when I listen to the tuner as well.

I've downloaded the service manual ( http://www.fast-files.com/getfile.aspx?file=114845 ) , but it is a bit difficult for an amateur to understand the schematics. I plan to replace the caps (Assuming it one of the filter capacitors at fault? But where might they be located?) , except for the biggest ones which are (12000 UF). They are kind of more expensive than the machine itself.

Maybe somebody can point me in the right direction to fix this problem? I have only a multi meter and a soldering iron. Any help is appreciated.
 
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It's not those big caps. They are for the power supply and would affect both channels. Take the top off and find the speaker protection relay. It clicks about 4 seconds after power on. With the unit acting up, tap on it with a wooden pencil or similar - be careful with metal objects! You may have different results from speakers being turned on because of the load being different. Try it with headphones and speakers together. Same result? Many times the protection relay will get funky contacts or cold solder joints.
 
Seems like you were right, it is one of the relays that is malfunctioning. If it tap or press on it a bit, then both channels work well.

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Unfortunately it is so deep on the main board that I would have to take the whole thing to pieces to replace it... Ah well, at least the problem could be solved. Big thanks redk9258 !!!
 
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No lower panel to take off for access to the bottom of the PCB?. I looked at the service manual and there's a lot of stuff going on in there. Can you post a picture of the inside with the relay pointed out?
 
You might be able to get the cover off and clean the contacts with deoxit and a business card or 1000 -2000 grit sandpaper.
 
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