The one 43 meter movement that I opened up had a 200 ohm resistor in series
with the movement. That particular meter reads way low, 20 to 30% low and
doesn't seem to have a sticking problem. It was removed from a bird 43 when
a new replacement was put in.
The other two bird 43 meters that I have, one reads about 10% low and the
other about 5% low with 30 microamps applied to the meter.
I am wondering what would cause them to read that low.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Steve Thompson
> Sent: Monday, May 07, 2007 6:46 AM
> To: amps@contesting.com
> Subject: Re: [Amps] Bird wattmeter
>
> I think the 1350 ohms Peter measured is the movement itself - the spec.
> is 1400 ohms, 30uA. I don't think there's any extra resistors in there.
>
> I forget who started the thread, but how far off fsd is the indication
> at 30uA?
>
> Could it be worn or dirty pivots or work hardening in the hairsprings?
> Maybe some sort of damage from being pinned against the end stop too
> often :-)
>
> Steve
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