No, Bryon, I have not. This is weird. One day it works and the next day it
exhibits this condition.
Static electricity seems to be the standard reply from most of the Collins
group, however.
This has got to be the answer but it not come from me wiping the meter face.
Dave, W3ST
Publisher of
I tried another meter and it worked fine.
That is what is troubling. I am going to take this meter and place it in
another transmitter to see what it reads.
Will report back to you.
Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com
Nets:
It would be interesting to see exactly how much current is flowing
through the meter. Try hooking the lead from the smoothing choke to
the other terminal of the meter. Now, if the same phenomena is present
you can read the current flow. Also, it just seems like an interesting
thing to try
Connecting the lead from the smoothing choke to either terminal results in
the same downward reading.
A mica cap is across the meter and I removed it as well.
I am going to hook this meter to the plate lead of the Collins 30K-1
transmitter today to see what happens.
Will report the results
Dave-
Could there be a leakage path to ground? 4KV is a lot, so if there was a high
resistance path to ground, some current could flow back to the chassis...
If you remove both leads, can you measure any resistance from the positive
lug to the chassis? Does the meter deflect when you do this?
But.. To get the correct input power (required in broadcasting) you must
measure plate current not cathode current. Properly insulated meters are
safe and reliable. I agre its either static or magnetic field problem.
W3LW
W3LW
At 02:11 AM 1/2/05 -0400, you wrote:
John, thank you for
Just remember that when you put the meter in the cathode circuit it measured
combined plate screen current.
Bob Macklin
K5MYJ/7
Seattle, Wa.
REAL RADIOS GLOW IN THE DARK
or Grid/cathode current, in the case of triodes ;-)
73 = Best Regards,
-Geoff/W5OMR
I would think that if enough current went through
the meter to reverse the
magnet, it would have melted the coil...
Maybe it was reversed by a magnetic field rather than
a current through the coil. The fridge in my
daughter's house became magnetized after the house was
hit by lightning.
Today I found an open 20K/150 watt resistor (one of two screen dropping
resistors) that was open.
Since the 4-400A's did not have screen voltage the high voltage soared which
may have caused the plate current meter to show negative current - too much
voltage floating around inside the meter.
I
- Original Message -
From: David Knepper [EMAIL PROTECTED]
To: Collins Mail List [EMAIL PROTECTED]; Discussion of AM Radio
amradio@mailman.qth.net
Sent: Sunday, January 02, 2005 11:42 AM
Subject: [AMRadio] The Solution
Today I found an open 20K/150 watt resistor (one of two screen
Hi David,
This was a great thread and I am glad you found the problem.
I don't remember seeing a 20V when I was over there about a year ago. Did
you get it recently, or is my memory just faulty? I remember the Western
Electric BC transmitter.
Bill
KA8WTK
Tallmadge, Ohio
- Original
I do hope that once that I install the 20K resistor that the 20V-3 will
again be purring.
I got the 20V-3 last year and it stands proudly next to my Western Electric
451A-1. We are building a studio downstairs for the heavy iron that is
upstairs, like the spare 30K-1 and the receiver deck with
From the local club mailing list. Seems it is true.
Guess they think we are all lunatic old men that
spend too much time in the basement.
(Myself, I'm not too old, nor do I have a basement)
Tom NU4G
This week's issue (December 27) has an article on blogs on page
109.
In
If you measure current from the filament transformer center tap to ground,
you'll have not only cathode current, but plate current, as well. Just
look
over at the grid current meter, subtract that from the plate meter, and
there's
your plate current, AND it's in a nearly ground potential
What your speaking of Don is shown in the following article.
http://www.qsl.net/wa5bxo/pptriodes/pptriodes.htm
This article was started some time ago, for what reason I don't
remember. I never had the chance to spend a lot of time with it so it
probably has a lot of mistakes.
What your speaking of Don is shown in the following article.
http://www.qsl.net/wa5bxo/pptriodes/pptriodes.htm
If you measure current from the filament transformer center tap to
ground,
you'll have not only cathode current, but plate current, as well. Just
look
over at the grid current
Installed a new 20K/200 watt resistor in the screen circuit to the 4-400A's.
There are two of these resistors in series - I replaced the other one some
time ago. The problem was none other than an open resistor. I did see a
whitish power on one end of the resistor which is a sure sign that the
I am not embarrased but otherwise, I resemble that remark. If the shoe fits!
K0NG .
Quoting Patrick Jankowiak [EMAIL PROTECTED]:
From the local club mailing list. Seems it is true.
Guess they think we are all lunatic old men that
spend too much time in the basement.
(Myself, I'm not too
I think it would have to be, Tom. Then there should be an audio choke
between the screen supply and the screens.
-Larry/NE1S
Tom Elmore wrote:
The unit I have has a separate B+ supply for the screens. So would this be
self-modulating then?
-Tom
- Original Message -
From: ne1s [EMAIL
19 matches
Mail list logo
