It is IMPOSSIBLE to get "precisely" 5 volts and 6.3 volts at the same time.
What ever your using to measure these voltages says you are, but your not.
Gary
"Antonio I0JX" wrote in message
...
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.

Line voltages were slightly less when the 516F-2 came out. And, tubes
were
much cheaper.

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.

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.

73, Colin K7FM


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