Peter,
He said though, "60 cycle?". He isn't for sure what the frequency of the hum
is. With one diode open, you would essentially have a half wave power supply
only conducting on every cycle. If you have a filter going bad to the point it
isn't filtering the AC, then you would have a 120 Hz hum. The hum would grow
greater under load because the filters aren't charging up to support the
supply. Thus, you'd have a greater voltage drop since the filter caps control
the voltage sag along with the transformer. If the filter caps were all good,
and you put a half wave rectifier to them, I'm not sure it would sag that much.
I would check to make sure that the screws used to mount one of those panels
didn't puncture the side of a filter cap since his problems started after
applying the wood panels. A screw could have cut a trace in two on a PC board,
or could have damaged a wire inside. I just can't see a rectifier going open
just setting.
Best,
Will
*********** REPLY SEPARATOR ***********
On 4/20/06 at 11:39 AM Peter Chadwick wrote:
>Like Peter, I would suspect one of the diode stacks has gone open
>circuit. If it was the filter capacitors, the hum would be 120Hz.
>
>If it was the cat, the hum caused by purring is modulated at a lower
>frequency!
>
>73
>Peter G3RZP
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|