[TenTec] Century 21 audio hum

Josh Gibbs gibbsjj at gmail.com
Tue May 30 17:49:25 EDT 2017


Hi Stuart,

I know that I can test the diodes, but getting the power board out for
testing is a lot of work. I would definitely do it if I suspected the
bridge rectifier, which is why I asked about symptoms of a bridge rectifier
that has an open diode. I would think an open diode would be noticeable
when looking at the ripple? I don't have any experience with this - I tried
searching for this and most stuff I found said it would act like a 1/2 wave
rectifier -- ripple would be 60 Hz.

Appreciate the help!

73,

-Josh WA7FPV

On Tue, May 30, 2017 at 2:11 PM, Stuart Rohre <Rohre at arlut.utexas.edu>
wrote:

> Do you have diode test function on your DMM?  if so, you can inspect each
> diode in a bridge in circuit, or at worst take off one lead from Plus (+)
> bus.  Silicon diodes will show 600 mv across each one, germanium 300 mv.
> Make sure the capacitor following the bridge is discharged before testing,
> and radio is unplugged from everything.


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