Buzzing transformer in Teac AG-790 receiver

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maurycy

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Joined 2005
I just bought Teac stereo receiver model AG-790. This is a basic stereo receiver without any fancy features. It works fine except that there is buzz coming from the trafo (not toroidal but one of those square transformers). This is when unit is on and also when I switch it to standby mode. When I turn it off via the main switch, the buzz goes away. Also the receiver is warm to touch even on standby in the trafo area.

Buzz is not very loud but it is loud enough for me to think that it shouldn't act like that. I would categorize its noise as annoying at night.

I have a very basic knowledge of electronics, I know how to solder and use multimeter (at least its basic functions). Is there anything I could check myself?

Thanks.
 
Piercarlo

Piercarlo

Member
Joined 2006
maurycy said:
I just bought Teac stereo receiver model AG-790. This is a basic stereo receiver without any fancy features. It works fine except that there is buzz coming from the trafo (not toroidal but one of those square transformers). This is when unit is on and also when I switch it to standby mode. When I turn it off via the main switch, the buzz goes away. Also the receiver is warm to touch even on standby in the trafo area.

Buzz is not very loud but it is loud enough for me to think that it shouldn't act like that. I would categorize its noise as annoying at night.

I have a very basic knowledge of electronics, I know how to solder and use multimeter (at least its basic functions). Is there anything I could check myself?

Thanks.
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Should be enough. That you really need is remounting the transformer in the assembly with a little sheet of rubber between is body and the remaing chassis. Remember of restoring electrical connection beetween transformer body and chassis if present (as usually is).

Usually in receivers of this kind transformers sucks but its replacement is not recommended because the stabilizing circuit (even this usually not a great electronic design) is builded around the parameters of its transformer and replacing this with a good one usually lead to a stabilized thermal surcharge because of the better load factor of normal, standard quality transformers (if you want replace original transformer with a better one you should plain a little reinforcement of thermal dissipating capabilities of the voltage stabilizer).

Hi
Piercarlo

POST - I've just read now that in transformer area is warm even in stand-by. Then you should check for eventual surcharges around it or, in worst case, IN it. Disconnect transformer from circuit and test it with normal main voltage. If transformer is again buzzy, then you should replace it with a new one.
 
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