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 just to see if you get flow at all.
By any chance, is there a capacitor across the terminals? If so, what
happens if you remove it?
Alan
WA2DZL
On Jan 2, 2005, at 1:25 AM, David Knepper wrote:
What is strange about this condition is that the meter deflects
correctly
when connected to a multimeter set on ohms.
Positive or red lead to the postive terminal and negative or black
lead to
the negative terminal of the meter.
The 4,000 volts when applied, however, causes the meter to deflect
incorrectly. When I tune the transmitter, I can see that the meter
pin does
vary but it will not move from the left of zero.
The question that I would have is whether or not anyone else has
experienced
this problem, ruling out static electricity on the meter face.
I did remove the meter to clean both the inside and out of the glass
but
that did not help.
One day the Collins 20V-3 worked perfectly and the next day, as they
say,
the plate current meter went "nuts."
By the way, the R.F. ampere meter is acting strange as well. The
needle
quivers as if it is charged with static electricity.
Could it be that the meter panel which is insulated phenolic needs to
be
discharged somehow. I am lost at this point.
I am inclined to believe - as so many of you suggested - that the
meter or
meters have contracted static electricity.
Thanks
Thanks to all who have replied.
Back to the drawing board as they say.
Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com
Nets: 3805 Khz, Monday/Wednesdays 8 PM EDST
14250 Khz Saturday, 12 Noon EDST
----- Original Message -----
From: "David Knepper" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" <amradio@mailman.qth.net>
Sent: Sunday, January 02, 2005 2:11 AM
Subject: Re: [AMRadio] You Won't Believe This
John, thank you for this.
Collins engineers did not adhere to safe operating practice when they
placed
the 800 ma meter in the positive lead going to the R.F. choke. It
should
have been in the negative lead as you suggested.
Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com
Nets: 3805 Khz, Monday/Wednesdays 8 PM EDST
14250 Khz Saturday, 12 Noon EDST
----- Original Message -----
From: "John Coleman, ARS WA5BXO" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" <amradio@mailman.qth.net>
Sent: Sunday, January 02, 2005 12:31 AM
Subject: RE: [AMRadio] You Won't Believe This
I gather from the text about the HV meter and current meter that the
current meter is above ground by 4000 Volts. I know that there are a
lot of special mounting devices and hardware for this purpose but I
still feel that it is a bad idea. I have always made sure that HV
current metering was done in the current path that is close to ground
potential. As a further precaution it is a good idea to put a 50
Volt
or less avalanche diode across the meter in case it should become
open.
As for the defection phenomenon, it might even be possible that the
continued HV on the meter has put permanent static charge in the
molecular structure of the plastic. If this is the case then any
connection even a ground on the meter would cause a deflection. In
any
case I would move the current metering circuit to the cathode
circuit or
the negative return of the power supply. Modification of initial
circuitry sometimes requires lifting all the ground connections of
filters and/or chokes to get a floating ground and then passing that
through the meter for current readings. I my opinion it is well
worth
the effort. I always put chokes in the negative lead of power
supplies
as well.
It is an interesting phenomenon though. So please let us know what
you
do find as the cause.
73, John, WA5BXO
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of David Knepper
Sent: Saturday, January 01, 2005 5:31 PM
To: Discussion of AM Radio; Collins Mail List
Subject: [AMRadio] You Won't Believe This
That is right, only one lead connected and the meter is reading
negative
current. I switched this lead to the negative post and the meter
still
deflects downward past zero.
______________________________________________________________
AMRadio mailing list
Home: http://mailman.qth.net/mailman/listinfo/amradio
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:AMRadio@mailman.qth.net
______________________________________________________________
AMRadio mailing list
Home: http://mailman.qth.net/mailman/listinfo/amradio
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:AMRadio@mailman.qth.net
______________________________________________________________
AMRadio mailing list
Home: http://mailman.qth.net/mailman/listinfo/amradio
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:AMRadio@mailman.qth.net
