Colin,

from the various answers I receive, it seems to me that I am not able to =
explain myself well.

Let me put it this way. I have a variable transformer (VARIAC) and I =
adjust the mains voltage until I get precisely 5V and 6.3V on the =
filaments.

At that point the DC high voltages are both significantly higher than =
what stated in the manual. The transformer AC voltages are also too high =
and well matching the DC voltages, so the problem is not in the =
rectifier.

I was just asking whether someone has measured the 516-F2 AC voltages at =
nominal mains voltage.

73

Tony, I0JX


"COLIN LAMB" ha scritto nel messaggio =
ink.net...
Collins designed the 516F-2 for voltages less than today's typical =
line
voltage. This is because a certain minimum voltage is required for =
good
performance, and Collins wanted good performance even if the line =
voltage
was less than what we now consider normal (110 volts or 220 volts). =
The
specified voltages were actually a "minimum" voltage rather than =
nominal.
=20
Line voltages were slightly less when the 516F-2 came out. And, tubes =
were
much cheaper.
=20
Today, tubes are much more expensive and difficult to obtain, so it is
important to not exceed the voltages to provide maximum life for =
tubes.
=20
I built my own substitute power supply for my KWM-2A. Although I have =
solid
state rectifiers, I have a timed delay to allow full warm up of the =
tubes,
prior to application. And, I monitor the filament voltages and use a
step-start. The result is that I have not had to change a tube in my =
KWM-2A
in about 25 years, even though I used it daily for almost 10.
=20
73, Colin K7FM
=20
=20
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