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Posted by David Sherman on Monday, December 01, 2008 at 12:05:06 :
In Reply to: Thanks Dennis! Great stuff!!! No txt posted by Drew M. on Monday, December 01, 2008 at 08:35:13 :
This D. Sherman is "David", not "Dennis". I keep forgetting to put "David" rather than "D." as my forum name. Sorry.
Anyway, one thing I left off was that it's better to test them with a variable resistor than a pair of fixed ones, because with a variable one you can "dial" the pointer slowly across its full range in both directions and see if it sticks anywhere. Gauges that stick are really frustrating. A 100 ohm potentiometer is good for the oil and gas gauges, and a 5000 ohm one for the temperature gage.
I've fixed gauges and meters that have sticky spots, but it's really not worth it. The covers are swaged on, so you have to pry them off, and then the stickiness is usually due to tiny specks of rust that have gotten stuck in the gap of the magnet inside it. Blowing it out with air strong enough to get the dirt out usually wrecks the springs, which are like the hair spring in a watch, and taking it completely apart and cleaning it is like cleaning a mechanical watch -- you have to have tiny tools, a perfectly clean bench, and a magnifier.
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