On 6/6/2011 1:17 PM, Carl wrote:
> It sounds like you may have an open cap in the string.
>
YES! You'll also be getting reports of hum (or a buzzy CW note).
Don't try testing by voltage measurements. You need an old fashioned
analog VOM, like a Simpson 260 or even a cheaper equivalent. Let HV
bleed for a long time, then open it up and use the middle Ohms scale to
measure resistance of each cap in the string, first in one direction,
then reversing the leads. What you're watching is the charging current
each time you reverse the leads, and you want to see a lot of meter
movement (that is, very low resistance readings that gradually decay to
high resistance readings. Measure them all (no need to write numbers
down) and see what they look like. When you find one that doesn't move
as much, that's the bad one. It's common to find one or two bad ones
while the rest are just fine and have plenty of life left in them.
73, Jim K9YC
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