[Heathkit] Heathkit AT-1 Meter

[hwhall at compuserve.com]

Sounds like first suspect ought to be the movement's spring and zero-set adjustment. I'd suspect that the spring has detached at one end or broken. But you've looked inside & said you found nothing amiss.

Does the needle behave normally when current is flowing thru it? E.g., does the needle go to zero or nearly so when a very small, say 0.5 ma or 1 ma, current flows thru it?

Does the needle settle on "noon" no matter what the orientation of the meter body is? E.g., is it still pointing midscale if the meter is on its side or upside down?

When it returns to "noon" does it move slowly or fast? Does it bounce around "noon" like its oscillating on its spring? Or does it settle quickly onto noon?

If you waggle the meter body, does the needle swing freely around noon or does it move jerkyly like there's maybe an obstacle preventing free movement?

 

 Wayne
WB4OGM

 

-----Original Message-----
From: Mark K3MSB <mark.k3msb at gmail.com>
To: Heathkit List <heathkit at mailman.qth.net>
Sent: Tue, Jun 28, 2016 7:23 pm
Subject: [Heathkit] Heathkit AT-1 Meter

I'm finishing up a Heathkit AT-1 transmitter.

The meter tested good; I get full scale deflection at 10 mA, and a measured
resistance of about 220 ohms.

I tested the radio for the first time tonight and the meter acted normally.

Somewhere along the line, the meter decided to stay about "high noon" even
when power is off. The meter still tests good, and reacts as it should
during tuneup.

I removed the meter from the radio, and put a magnet near the meter and I
can get the meter to go to zero, but it returns to "high noon" when I
remove the magnet.

Ideas? Some kind of residual magnetism?

73 Mark K3MSB
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