CHT-15R Sub woofer problem

[flat_listener]

Hey everyone,
I've got a sub woofer that doesn't function properly, here's a rundown of the symptoms and the tests that I've performed:

1) Sub woofer is humming during operation, the power light is on.
2) The problem occurs regardless of whether its hooked up with the high level input or the line input or no input.
3) I have tested the sub with another receiver, but the result was the same.
4) Power is set to "On", not "Auto-On"

These facts have led me to the conclusion that the plate amp has gone bad.
I pulled the amp out of the sub woofer, and I can't see any damaged or fried components, bad solder joints, etc. It looks fine.

I'm looking for advice from people who have encountered a similar issue, and what component they suspected was the cause.
I can't speculate what might be causing the problem that I'm having.

Please chime in with any experience or advice that you may have, even if it's directing me to another forum!
Thanks for any help that you can offer.

 

[Deleted member 79034]

The Hum sound usually happens when there is not proper earthing. I suggest you check that first.

I had a similar issue with my sub which was brand new then. I connected to a diff power outlet which had proper earthing and the hum disappeared.

I doubt there would be any issue within the sub.



Sent from my C6902 using Tapatalk

 

[flat_listener]

Let me state that my definition of "hum" is "I can barely hear any LFE audio". I can confirm that sound is playing through the sub woofer... just power noise.

 

[hydrovac]

I would think blown output transistors...

You need a circuit for the amp at least. These days unlike the days of old they seem hard to come by. Without at least a circuit diagram you are stuck.

A service manual if you can get one is very helpful.

This is a class D amp, and most plate amps are, they are very difficult to service.
If the problem is in the switching power supply of these units, they are virtually impossible to service, and not worth the time.

Basically those types of units are disposable devices and not worth the trouble to service.