[AMRadio] Requium for Tranny?

[Gary Blau]

If you have an audio oscillator and ac voltmeter handy, inject 60Hz at
1V into the primary and measure the secondary.  That should help you see
if there's a ratio/shorted turns problem.

Next would be to slowly bring the xfmr up to full input voltage with a
variac, with a light secondary load.  If it survives the voltage test
then the trouble is likely in the load somewhere (rectifier, etc.).

g 

Dave Aabye wrote:
> 
> Good morning all,
> 
> I need some advice.
> 
> Earlier today my Viking 500 tripped off with the familiar odor that we
> have all come to dread.  I only lost HV.
> 
> After I got the cover off the PS-Mod unit, I was surprised to see
> nothing unusual.  Then I started sniffing, and that led me to the HV end
> of the plate transformer.  I removed the end cover and again saw nothing
> unusual....only the odor, which by then was beginning to dissipate.
> 
> Resistance measurements lead me to think that some windings may be
> shorted.  One side to center tap reads 110 ohms.  The other reads 95.
> The manual says 100 on either side.  The HV secondary shows infinite
> resistance to ground, but that is with no juice applied.
> 
> What I'm wondering is whether the 15 ohm difference is conclusive.  If
> not, what other tests might I make without risking further damage?
> 
> Thanks in advance for any advice,
> 
> Dave, W4QCU
> Oak Ridge, TN