OK Peter-
Yes, I will reserve one for your friend until I hear from you. No rush,
I will hold your meters until I get your letter. Thank you.
- Original Message -
From: "Peter Wittenberg" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio in the Amateur Service'"
Sent: Monday, Februa
Byron, great. I will try to go to the post office tomorrow and send you a MO
for the $60.
You mentioned that you have more. I have a buddy that might need one of
these as well. So could you hold another for a few days???
My address is:
Peter Wittenberg - K2LRC
117 Bay Drive
Annapolis, MD 21403-44
OK Peter -
I have you down for two. Please allow 10.00 for well packed Priority
Mail, for total of 60.00 to Byron Tatum, 2142 County Road 367, Alvin, TX.
77511. Thanks.
- Original Message -
From: "Peter Wittenberg" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio in the Amateur Servi
I will take both of the meters if they are still available.
Peter K2LRC
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Byron Tatum
Sent: Monday, February 19, 2007 10:25 PM
To: AMRadio@mailman.qth.net
Subject: [AMRadio] FS-NOS TV-7 Tube Tester Meters
Hel
>From Joe w5jdy in Okla. My experience with a modulator.I replaced the
audio drive transformer in a Viking II (the one feeding the grids of the
final modulator tubes) with a brand new in the box Hammond Transformer from
Antique Radio in Tempe Arizona... I had mod current but distorted audio
>I notice from the schematic, that there is also a tertiary winding which is
>fed to the the driver stage. Seems a long shot, but could it be out of
>phase?
Good thought - I tried it both ways, no difference.
>Also, what are you using to measure the capacitor. A digital capacitance
>meter will
Hello-
I have NOS TV-7 tube tester meters for sale. The meters are in boxes sealed
in metal foil with a 1983 date code.Packages are in excellent dry shape. The
meter is made by A&M Instruments, model 365-491. These meters are physically
identical {size and scaling} as the one in my TV-7D/U a
I notice from the schematic, that there is also a tertiary winding which is
fed to the the driver stage. Seems a long shot, but could it be out of
phase?
Also, what are you using to measure the capacitor. A digital capacitance
meter will mask a poor power factor. In other words, the cap could s
> My first 75m contact with the vertical was today at mid-afternoon, with
> Howard, W3HM. Can't wait till tonight to see what kind of signal reports
> I
> get at various locations over the country.
Or maybe even from Europe!
There are AM stations listening over there too...
___
[EMAIL PROTECTED] writes:
> Mod Reactor shorted?
Ohms-out OK on a Simpson 260, but perhaps a problem under higher voltage?
> The cap to ground off the bottom of the Mod secondary good?
It measures the expected 4 uF value.
Bob wrote:
>Does that thing use feedback?
Yes, and I've tried it wit
After 25 years, I finally tuned the 127' vertical to 75! Ever since I first
put it on the air in 1982, I have used it only on 160, as a quarter wave.
Up in the AM Ghetto, the half-wave high dipole seemed to be all I needed,
since DX wasn't really much of a possibility. I never had any problem
probably just a loose nut between the chair and microphone LOL
just joking.. Geoff is a good friend, I gotta jab at him every once in a
while!!
I think the problem is still with him though and in a IM QSO with him
yesterday we discussed the possibility of bad mica's in the output stage.
This i
The more I look at this hv transformer the more I think it may not be as
hefty as I was thinking. It supplies only the screens of the two 828
modulator output tubes and the one 828 audio driver. It's possible the
transformer is no more than 200 ma. It's really not very big or heavy,
probably
Ya just gotta let the smoke out every now and then to be sure the legend
is true!
Thanks, you're right..
Rick
John Lawson wrote:
One think I just thunked is: I don't know if you have any really
small-current fuses, like 100mA or so - if you do, perhaps you could
put one in series with
On Mon, 19 Feb 2007, Gary Schafer wrote:
You had best have something to protect that microameter when you turn on the
supply as the capacitance of the transformer windings will look like a short
to the meter until the charge equalizes.
Running it up with a variac would be ok.
Yeah - and t
One think I just thunked is: I don't know if you have any really
small-current fuses, like 100mA or so - if you do, perhaps you could put
one in series with the meter - if there is a substantial internal short,
or even an accidental flashover - it's bound to kill the meter... don't
want t
You had best have something to protect that microameter when you turn on the
supply as the capacitance of the transformer windings will look like a short
to the meter until the charge equalizes.
Running it up with a variac would be ok.
73
Gary K4FMX
> -Original Message-
> From: [EMAIL PR
Bingo! That should tell me exactly what I need to know. Thanks, John!
Rick
John Lawson wrote:
Re: quasi-pseudo hi-pot testing of your transformer - if you have a
device that produces the required 800-1000 VDC - and can access that
voltage (such as a bench supply, one of the other power
Re: quasi-pseudo hi-pot testing of your transformer - if you have a
device that produces the required 800-1000 VDC - and can access that
voltage (such as a bench supply, one of the other power supplies in the
transmitter - or even a Ranger maybe) then [carefully!] attach the
positive lead
Okay.. I have decided the filament transformer in the GE may still be
okay. I've had it connected through a Variac at 100 volts (the stated
primary voltage of the transformer) for about 2 hours and it is barely
warm. I also have a 5R4 filament connected to it as it would be in the
circuit. I
Steve,
In cases like this I like to pull out my 1000X HV AC compensated probe.
There is a suitable probe on Ebay right now similar to mine:
Ebay, Item number: 320084300029. Mine is good for 15 kv whereas this one is
good for 7 kv.
A probe like this will allow you to use your scope and safely
A while back Geoff W5OMR was soliciting input on what might be the cause
for low output on his Viking II exciter. Although I may have missed it,
I never saw the resolution posted here.
Geoff, did you resolve the problem? If so, I'd be interested to know the
root cause.
-Larry/NE1S
__
Thanks for the heads-up on that one.
Healthfully yours,
Don W4BWS
- Original Message -
From: "Gary Schafer" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio in the Amateur Service'"
Sent: Monday, February 19, 2007 11:16 AM
Subject: RE: [AMRadio] Low modulation
Just a note about work bench tops if you happen to be doing this high
voltage testing on the bench. Some bench top surfaces like kitchen cabinet
counter tops that are made of formica are very conductive! Be careful.
73
Gary K4FMX
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:amr
Hi Steve,
Try applying 122VAC to the secondary through a 1K, 20 watt power resistor. The
voltage to the windings should not drop much
from the no-resistor readings. I am guessing that you should see at least 100V
on the secondary and 67V on each half of the
primary, and these figures may even
That's a good idea! I have several of those transformers. I'll set one
up with the Variac and see what I get.
Thanks!
Rick
Bob Bruhns wrote:
Instead of looking for a 100V in, 5V out transformer, use a 120V in, 6.3V out
transformer with the same current specs. It will
work out almost exactl
Instead of looking for a 100V in, 5V out transformer, use a 120V in, 6.3V out
transformer with the same current specs. It will
work out almost exactly the same - you'll get 5V out for about 100V in.
Bacon, WA3WDR
__
AMRadio mailing l
To test the modulation transformer for sure, try high voltage a.c. on it.
The insulation may be breaking down at higher voltage, while appearing
normal at 110 v.a.c.
Using some clip leads or temporary wiring, set the mod transformer on the
floor away from the transmitter, so that it cannot ac
Hi Gary,
As usual, my description was lacking. The beast has five filament
transformers with all primaries wired in parallel. So, to adjust the
filament voltage you simply set the rheostat to 100 vac as indicated on
the filament voltage meter. So, GE has created a sure fire way (or so
the
Thanks, Geoff. That may very well be the key to this problem. The
filament transformer I need is a 100 vac primary (or multi tap as you
suggested) with a 5 vac @ 2.5 amp secondary. This is out of a GE
BT-20-A broadcast transmitter and they used a small potted GE
transformer. I seems they w
Kinda scratching my head here, if the primary voltage is passing thru a
rheostat, why the need for 100 volt primary trannys?
Regards,
Gary...WZ1M
- Original Message -
From: "ARS W5OMR" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio in the Amateur Service"
Sent: Monday, February 19, 2007
Steve,
Mod Reactor shorted?
The cap to ground off the bottom of the Mod secondary good?
Bill
KB3DKS/1
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