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Old 9th Sep 2013, 11:41 am   #15
Pamphonica's Avatar
Join Date: Mar 2008
Location: Virginia Water, Surrey, UK.
Posts: 2,149
Default Re: AVO VCM163 - Some faults I have had

I would like to re-iterate the fault advice regarding wires trapped under mounting pillars.

My VCM163 had an odd fault when I got it. The Vg was definitely very low, if not zero, at all settings. It turned out to be the wire from the Vg circuitry trapped under a mounting pillar en-route to the switches. Over time the insulation was crushed and a short developed.

Finding the location of a short to earth can be hard, but if you can make or borrow a low-ohmmeter (say 0-100 milliOhms) it makes the job a lot easier. Mine came from an auction at about 10 or 15 and has been invaluable for finding shorted power supply decoupling caps on tightly packed circuit boards.

- Jeremy
Jeremy, G8MLK, BVWTVM Friend, VMARS, BVWS Secretary.
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