There are very few transformers out there that are rite on the nose or
within a few percent. Collins is not one of them, I assure you. Secondary
voltages are determined by the VPT (volts per turn) on the primary. Primary
voltage varies and lets not forget frequency varies also. Being a
transformer rewinder, I see allot of Collins stuff. The 516F-2 power supply
was NOT one of Collins best attempts. They used what ever transformer was
available and the cheapest, dollar wise. The vpt on the 516F2 is .44 volts.
With 14 turns that equals 6.16 volts. At 15 turns that equals 6.6 volts.
This is at no load. I have rewound several of the 516F-2 power transformer
and NONE of them are "rite on".
Regards,
Gary

"Antonio I0JX" wrote in message
...
Differently from what you think, filament voltage must stay within a few
percent from nominal as it is very critical for tube life You can be sure
that Collins designed the transformer for exactly 5V on the rectifiers and
6.3V on the other tubes, plus /minus just perhaps one percent, when line
voltage is nominal.

So, if I measure exactly 5V and 6.3V on the filaments, it means that my line
voltage is OK. And I also have an accurate line voltage meter that witnesses
that.

So, differently from what you think, the problem is that the RATIO between
the transformer high-voltage and filament voltage, which appears to be
higher than it should be

Tony, I0JX

"GBrown" ha scritto nel messaggio
...
A 10% increase in line voltage will affect the hv secondary but not the
filament voltage as you mite think. See below.
120 line X 10% = 132
750 hv X 10% = 825
6.3 filament X 10% = 6.9 Still within the ballpark.
Note, most all transformer filament voltages are not what you mite think
they are. For instance, 6.3 volts could be as much as 7 volts, 13.8 could
be
15 volts, 5 volts could be as much as 5-1/2 volts. This also holds true
with
hv secondary. Line voltage fluctuations affect the transformer outputs,
before any regulation.
My two cents.
Gary


"Antonio I0JX" wrote in message
...
Can't understand that question: if filaments voltage is OK, it means that
line voltage is OK.

Tony, I0JX

"Scott Dorsey" ha scritto nel messaggio
...
Antonio I0JX wrote:
AC voltages do not vary whether using a solid state or tube rectifier.
=
By the way I still have the 5U4 and 5R4. My problem is that the AC =
voltages are high (and hence the DC ones).

Is your line voltage high?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."