Magnetized meter

[Casual Fool]

I have a battery tester meter (Mallory) that came from a retail store. The
meter is magnetized and now sits center scale, instead of over to the left.
Any solutions to return it to it's normal state. I tried reverse polarity-
it goes to the left, but then returns to center.

thanks

Hi There, Lets not discount the fact that there may be a small piece
of metal shaving that has worked its way into the center of the magnet
and is lightly brushing the coil assembly, making it stick. This is
more common than you think. a Simpson "S" meter on a Collins Amateur
Receiver I own had this problem. What really suprised me that the
Simpson meter had never been taken apart before, so this was a factory
included screwup!! After some head scratching, and finally taking the
meter out and the movement apart, and unbolting the two screws that
hold the coil assembly in, I was able to "wipe" the little piece of
metal out of the magnetic hole. I reasembled the unit, and its working
fine to this day.... Oh, BTW, since this is a battery test meter, I
highly doubt that the movement would be a "taut band type" as these
are mostly used on high $$$ wattmeters and bench test multimeters that
don't get bumped around alot. One more final thought.. You may have
had one of the balance wires fall off, and may be sitting in the
bottom of the meter. This item will look like a tiny wrapped coil, and
goes on one of the two prongs near the center of the movement..
Sometimes the parafin used to hold these non ferrous balance weights
fall off, also causing a meter to do what you have said.. Best Luck!
Anthony, WB8MLA

 

[Just Another Theremin Fan]

You all keep describing moving coil meters for this/these
"battery testers". This implies a high impedance meter.

An high impedance meter would be next to useless for
testing a battery except to give a rough indication of
its unloaded voltage output.

What is the part/model number of this device to see
exactly what it is?

 

[Fred McKenzie]

I have a battery tester meter (Mallory) that came from a retail store. The
meter is magnetized and now sits center scale, instead of over to the left.
Any solutions to return it to it's normal state. I tried reverse polarity-
it goes to the left, but then returns to center.

Mike-

It is not magnetized. Since you have shown that static electricity is not
causing it, there are two other causes I can think of.

1. It is a zero-center meter movement that is biased to one end of the
scale when turned on and working.

2. There are coil springs at both top and bottom of the meter shaft.
These springs oppose each other. One of them is broken.

Fred