[Heathkit] Heathkit AT-1 Meter

[hwhall at compuserve.com]

Is it just my eyes, or is there no spring at all in that construction? If not, then what did it rely upon to return the needle to zero when no current flows?
 
The mp4 clip doesn't seem to be running right here.


 Wayne
WB4OGM

 

-----Original Message-----
From: Mark K3MSB <mark.k3msb at gmail.com>
To: Wayne Hall <hwhall at compuserve.com>
Cc: Ronald Youvan <ka4inm at gmail.com>; Heathkit List <heathkit at mailman.qth.net>
Sent: Wed, Jun 29, 2016 5:38 am
Subject: Re: [Heathkit] Heathkit AT-1 Meter




Well,  I further disassembled the meter.   Here's some pix and a short clip to wow and amaze you...... 

www.k3msb.com/at1/front.jpg
www.k3msb.com/at1/bottom.jpg
www.k3msb.com/at1/top.jpg
www.k3msb.com/at1/side1.jpg
www.k3msb.com/at1/side2.jpg

www.k3msb.com/at1/clip1.mp4


I see no way to perform any adjustment.  loosening the small screw at the bottom of the meter does nothing.


I assume that the two small discs are magnets   I was thinking of holding one and attempting to rotate the other (or perhaps rotate the pointer).   Unless there is something that was magnetized during my tests, the only other thing that could have happened to the meter was a force which moved some of the parts, and an opposite force may help.    Of course, it could bust things too.....


73 Mark K3MSB









On Tue, Jun 28, 2016 at 11:09 PM, Mark K3MSB <mark.k3msb at gmail.com> wrote:

The meter glass,  face, etc was already removed before my last post.
The meter has a metal case with glass front.
Mark

On Jun 28, 2016 11:06 PM,  <hwhall at compuserve.com> wrote:

One more thing to try... Apply some moisture to the meter face. "Fogging" it with your breath might be sufficient. Occasionally, some meters can acquire a static charge on the meter face or body that pulls the needle out of place. Plastic body meters seem most likely to do that. Some folks recommend wiping on some thinned soapy water to prevent recurrence.
 

 Wayne
WB4OGM

 

-----Original Message-----
From: Mark K3MSB <mark.k3msb at gmail.com>
To: Ronald Youvan <ka4inm at gmail.com>
Cc: Heathkit List <heathkit at mailman.qth.net>
Sent: Tue, Jun 28, 2016 8:49 pm
Subject: Re: [Heathkit] Heathkit AT-1 Meter

Ron & Wayne

The needle moves a bit when I jiggle the meter.  When I blow on the needle
it move freely in the appropriate direction.

Using a battery and series resistor the meter fully deflects from "noon" to
the right.  Reversing polarity the meter fully deflects from "noon" to the
left.  The meter returns to "noon" quickly.

There is no adjustment of any kind that I can see.

I think the meter is original, it matches the pictures in the manual.

Orientation - I'll verify tomorrow but I'm pretty sure the "noon" resting
point doesn't change.

73 Mark K3MSB
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