[Johnson] BA transformer replacements

[Dr. John Harden]

Whenever I have a transformer fail I look at a new one by Stancor, etc.
If  I can't find a replacement I use Peter Dahl. They are expensive but
extremely dependable. Old transformers usually break down and I avoid
them.

When the first Collins 516F-2 power supplies came out the primary was
only 108 VAC!!!! The primary voltage went up over the years as Collins
was aware of the increase in AC line voltages to 120 VAC or more.

I recently restored a 516F-2 supply for use with my KWM-2A transceiver.
I use high-quality solid state replacements for the 5U4 and 5R4 that I
purchased locally at Ack Radio Supply. Naturally I use a variac
auto-transformer to set the AC. With only
103 VAC on the primary I get the rated 285 VDC and the 800 VDC out of
the supply key up.....Imagine where it would be with 120 VAC or more on
the primary!!!! Old transformers will quickly break down if the input AC
is too high...

73,

John, W4NU
Atlanta