[R-390] Line Level Meter

[Bob Camp]

Hi

Obviously if the poor meter got in the way of a fast moving object 
that's a problem. If it is physically intact I would bet that it can be 
fixed. The R-390 meters are a bit harder to pop open than the plastic 
face meters you see in a lot of commercial gear, but the guts of the 
beast is the same. More or less you have the mechanical meter movement 
and some wires. In some cases you have a resistor or two in there.

The meter movement is easy to check. If it wiggles when you rock the 
meter back and forth in your hand then the bearings and springs are ok. 
If it is pegged hard one way or the other you may have a problem with a 
spring. If it is sitting mid scale and not moving then it's come off of 
a bearing.

If the movement is mechanically ok then the problem often is a broken 
wire or a failed series resistor. Usually these problems are the most 
common and the easiest to fix. I suppose there are audio meters with 
diodes in them as well. Again that should be an easy fix.

The one you worry about is the meter armature winding burning up. If 
that happens then you have a bit of a problem. Other than stuff that 
has been really nuked (as in 10 amps does not go well through a 10 
micro amp meter ... trust me on this one) the armature rarely is the 
point of failure.

If you do open up the meter you may be overcome by an impulse to eat 
some of the glow in the dark paint. Be sure to open the meter in the 
presence of another adult incase this happens to you. Multiple reported 
incidences of this behavior are the most likely driver in the 
military's long standing policy of removing meters from equipment 
destined for disposal.  Again, you have been warned ......


	Take Care!

		Bob Camp
		KB8TQ


On Aug 10, 2004, at 8:39 AM, Larry and Jody Cogan wrote:

> Yesterday was an unlucky day.....found a dead line level meter on a 
> long
> inactive 390A.  Hoping today will be a lucky one and some lister will 
> have a
> meter they are willing to part with.  I do expect that it wont be 
> cheap.  If
> anyone can help, please reply off list.
>
> Thanks,
> Larry
>
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