Tom, assuming the power supply is a voltage doubler type, two caps are
charged through half of the diodes on one half ac cycle and the other two caps
are charged through the other half of the diodes on the other half of the
ac cycle.
If the caps on one side are shorted, the diodes on that side may be bad as
well. In fact, shorted diodes could have caused the caps to blow up. They
don't like ac instead of dc.
73, Gerald K5GW
In a message dated 1/20/2014 8:58:58 A.M. Pacific Standard Time,
w7why@frontier.com writes:
Hi Bill
I took the caps out. Two of them looked like they should - put the VOM
across them and the needle deflected, then slowly came back on the VOM.
The
other two went to zero ohms and stayed there, no matter which lead went
where. 73
Tom W7WHY
ORIGINAL MESSAGE: (may be snipped)
n 1/19/2014 7:46 PM, Tom Osborne wrote:
> Well - found the problem. Got 2 shorted filter caps.
REPLY:
Not wanting to second-guess you Tom, but that's a little suspicious,
although not impossible.
First are you sure they are shorted? Did you disconnect everything from
them so they are "floating"? And second, what is the actual ohms
measurement? Even a good electrolytic will not show an open circuit.
There is always some high value of resistance.
I spent 20 years troubleshooting things with electrolytic caps in them.
It's easy to be fooled. Been there, done that.
73, Bill W6WRT
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