[AMRadio] Component ID please


John E. Coleman (ARS WA5BXO) wa5bxo2006 at pctechref.com
Mon Dec 11 19:04:38 EST 2006


Jack,
 Check the meter with another meter and see if it is reading 1ma and is
accurate enough.  You can series up a DMM with the movement coil and a
resistor of a few thousand ohms and put a 5V in to the whole series circuit
to see if you're DMM and the meter movement under test is reading the same.
If it is accurate and is indeed a 1 ma movement then just forget the parts
in the meter (connect the movement direct to the terminals) and connect the
meter to the external 5 meg resistor.  In this lash up, the 5 meg resistor
will supply 1ma to the meter, when there is 5KV present, and the meter will
read 500.

Good Luck
John, WA5BXO

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Jack Schmidling
Sent: Monday, December 11, 2006 5:32 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Component ID please

John E. Coleman (ARS WA5BXO) wrote:
 >So perhaps the
> other device was another resistor to adjust the value so that the meter is
> more accurate than it was with just the one resistor.


Well, the bands are black (background yellow) blue. Which would be 17 
meg but it is also open and it is unlikely that both a comp res and a 
wirewound would be open.  So I presume it is a cap and if you say one is 
not necessary, I will just replace the 500k and call it fixed.  There is 
also a 5 meg from the hv to the meter.

Thanks,

js


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