JVC TH-C30

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HOBL
HOBL's picture
JVC TH-C30

Hey everyone, first time using this forum, I have been looking over some of the threads, you people know your stuff so I am hoping you can help me out.  I have a JVC XV-THC30 home theatre system.  This comes with an active subwoofer that is controlled by the main unit via an AV Compulink cable, looks like an S-Video cable to me.  Here is my issue, when I power up the main unit with the subwoofer plugged into the AC outlet, I see the lights come on the main unit as well as the green LED on the subwoofer, and then it proceeds to shut right down again.  I tried this a few times and got the power to stay on for a brief time to both units, when this happened I could hear a relay in the sub actually latching on.  I was able to play a DVD with limited audio for a few minutes then it shut down again, the relay unlatched.  Can anyone with any technical experience on this equipment give me a few pointers on where to start?  I have no O/P on one the speakers in the sub as well; I also noticed a capacitor on the main unit, C981 that seems to be bulged a little more than the others.  Thanks

HOBL
HOBL's picture
OK,

OK,

Here is an update.  I measured the resistance at the speaker O/P's, I have 42ohms across all speakers except the Right Front speaker.  Anyone have a drawing so that I can trace this back?  As well, I have not been able to find the source of the trouble as to why teh subwoofer will not power on.  Thanks

dans_repair_service
dans_repair_service's picture
The bulging cap is not a good

The bulging cap is not a good sign.  I don't have a service manual so I don't know where in the circuit, C981 is.  I suspect that it is a coupling cap though.  This would block any DC current and onlyu allow the AC component to pass.  If this is shorted, it would allow DC through and the protection circuits would shut down the unit.  Based upon your symptoms, I'd guess that this is what is happening.  Be careful though.  We don't know what caused the cap to go bad to begin with.

See if you can get a service manual or at least a schematic.  With that I should be able to provide more detailed help.

Dan

HOBL
HOBL's picture
Thanks Dan,

Thanks Dan,

 I found a few other components that show signs of extreme heat, one is a Diode that has turned the board a hard brown, I was going to unsolder one end and check it out, the other is a digital transistor.  I will let you now how it all works out.  Where can I get a service manual?

 Shawn

Tom Keating
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Shawn,

Shawn,

I'm having the same problem with the same unit. Have you solved the problem?

Jerry

HOBL
HOBL's picture
Not yet, I have it in the

Not yet, I have it in the garage now, all speakers work fine with DVD and CD but only one speaker works when I use the Fm radio. weird. As well, when I measure the resistance at the speaker terminal O/P's, I have 42 Ohms on each speaker with no AC applied.

 

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