[Drake] AC-4 voltage stability problem

[Larry Taft]

If other supplies of similar design are not fluctuating and the line 
voltage is stable then I would suspect a shorted turn in the HV winding 
that is intermittent.  The idea of listening with a receiver while 
observing the scope may give a better idea of what is going on.  As the 
voltage jumps around you should hear a bit of static on the receiver.  Try 
disconnecting the diodes and put a resistor load on the HV winding.  That 
removes the rest of the components from the test.

A possible way to send the supply to the Big Transformer in the Sky is to 
run the voltage up with a Variac and see if the problem gets 
worse.  Unfortunately, it probably won't get better.

73,

The Grinch    K2LT


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