[Collins] Meter repair

Dr. Gerald N. Johnson geraldj at weather.net
Thu Jun 25 22:17:15 EDT 2009


On Thu, 2009-06-25 at 20:49 -0500, Robert Nickels wrote:
> Dr. Gerald N. Johnson wrote:
> > Sometimes those can be cleared up with masking tape folded sticky side out and slide into the
> > gap, these days double faced tape might work. 
> I've fixed several using a thin flat toothpick with a piece of 
> double-sided tape attached to probe into the air gap, where there is 
> inevitably a tiny piece of debris (mostly likely magnetic) that is 
> interfering with the free movement of the meter armature.   An old meter 
> repairman taught me the secret of doing this work is to combine maximum 
> light and magnification with minimal caffeine!

And only on a day when you feel steady. The experienced men I've known
who were good inside meters had their good days and their bad days and
they knew when it wasn't profitable to touch the works of a meter.

Point is, the watchmaker could have steadiness to apply the same
technique of the double stick tape, because you can't go in the gap with
a magnetic tool and keep it controlled, wood and cellophane with stickum
on it(like double faced tape) are about the only tools that will be
successful in the gap. With a few inches of fresh tape, it may not be
necessary to see the bit of metal, just sweep the entire air gap inside
and outside the coil.

And since the magnet is strong, you won't make progress if there is any
magnetic debris on the bench within several feet of the opened meter.
> 
> 73, Bob W9RAN
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer



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