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Old 06-13-2007, 12:34 PM
Jonathan Jonathan is offline
AK Member
 
Join Date: May 2005
Location: Pennsylvania
Posts: 326
Hello Phil,

The capacitor that failed is C225A. I can't remember if I had it backwards, but all the large capacitors all have their polarity correct. I made sure of that because not only are they more expensive to replace but they can fail in a more dangerous manner because they store more energy. I'm almost certain every electrolytic is the proper polarity, because thats one thing I'm careful about.

In place of the two 40uF capacitors that connect directly from the rectifier output to -100V I have an 80uF 450V electrolytic. After the field coil I have a 120uF 450V electrolytic instead of the 40uF and 80uF.

The pots I'm talking about are the horizontal and vertical centering pots. This was my silly mistake not to specify. Since they both measure 20 ohms they should be fine. Hard to believe that most of the set's current goes through these pots. I have to have a wiring mistake somewhere, I just can't find it.

Since C225A failed it was either backwards or there was more than 50V across it. There should only be 5V across it, and if there is more than 50V across it then the bleeder resistors could be at fault. I remember when I did power it up to measure B+ it was unusually high, about 100V higher than it should be, but I also remembered the bleeder resistors tested good. More testing needs to be done.

Thanks.

Jonathan
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