[AMRadio] [AM Radio] Old Iron

[JAMES HANLON]

A good way to test a transformer with a 120 volt "primary" winding is to put a 120 volt light bulb in series with that primary and then to power it up with no load on any of the secondary windings.  If there are no shorts in any of the windings, primary or secondary, there will be very little current pulled by the primary and the bulb will stay "dark."  There will also be very low voltage drop across the bulb.  One can, if you wish, measure the resulting voltages across the primary and the secondaries to see how the transformer is doing.
 
On the other hand, if there is a short in any one of the windings, the current drawn by the primary will be high and the bulb will light to nearly full brilliance.  Almost all of the voltage drop will then be across the bulb and very little voltage will appear across the transformer primary winding.  The bulb will act as a variable resistance to protect a faulty transformer from self destruction.
 
If the transformers are all OK, it's not completely obvious that the entire 32V might not be recoverable.  A good clean up might do wonders.
 
Jim, W8KGI