[Amps] 811H pops fuses

[TexasRF at aol.com]

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 at 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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