The DC output voltages being higher than what reported in the Collins =
manual (i.e. 360 VDC and 900VDC), I decided to directly measure the AC =
voltages on the rectifier plates.

During receive, I measured somewhat less than 2 x 400VAC and 2x1000VAC =
(filaments voltages are OK, i.e. 5V and 6.3V). So the higher DC voltages =
are justified.

Does anybody recall having measured said AC voltages?

Thanks and 73

Tony, I0JX

Are the rectifiers solid-state or the original tubes? The manual says
to expect a 12% increase in voltage using solid state rectifiers. Also,
someone, along the way, may have changed the p.s. to capacitor input,
vice choke, in the filter sction??? Regards de K3HVG

Antonio I0JX wrote:
The DC output voltages being higher than what reported in the Collins manual (i.e. 360 VDC and 900VDC), I decided to directly measure the AC voltages on the rectifier plates.

During receive, I measured somewhat less than 2 x 400VAC and 2x1000VAC (filaments voltages are OK, i.e. 5V and 6.3V). So the higher DC voltages are justified.

Does anybody recall having measured said AC voltages?

Thanks and 73

Tony, I0JX

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).

Tony, I0JX

"K3HVG" ha scritto nel messaggio =
...
Are the rectifiers solid-state or the original tubes? The manual says =

to expect a 12% increase in voltage using solid state rectifiers. =
Also,=20
someone, along the way, may have changed the p.s. to capacitor input,=20
vice choke, in the filter sction??? Regards de K3HVG
=20
Antonio I0JX wrote:
The DC output voltages being higher than what reported in the =
Collins manual (i.e. 360 VDC and 900VDC), I decided to directly measure =
the AC voltages on the rectifier plates.
=20
During receive, I measured somewhat less than 2 x 400VAC and =
2x1000VAC (filaments voltages are OK, i.e. 5V and 6.3V). So the higher =
DC voltages are justified.
=20
Does anybody recall having measured said AC voltages?
=20
Thanks and 73
=20
Tony, I0JX
=20

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."

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. =3D
By the way I still have the 5U4 and 5R4. My problem is that the AC =
=3D
voltages are high (and hence the DC ones).
=20
Is your line voltage high?
--scott
--=20
"C'est un Nagra. C'est suisse, et tres, tres precis."

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."

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


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04

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
=20
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% =3D 132
750 hv X 10% =3D 825
6.3 filament X 10% =3D 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
=20
=20
"Antonio I0JX" wrote in message
...
Can't understand that question: if filaments voltage is OK, it means =
that
line voltage is OK.
=20
Tony, I0JX
=20
"Scott Dorsey" ha scritto nel messaggio
...
Antonio I0JX wrote:
AC voltages do not vary whether using a solid state or tube =
rectifier. =3D
By the way I still have the 5U4 and 5R4. My problem is that the AC =
=3D
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."
=20

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
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04
=20

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."