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38-12 can caps?
#1

Ok This one has 2 can caps one is 12 mfd @450v the other is 4 mfd @450V In the picture below the cap in green has a negative lead and the center is for positive but the one in red seems to only have positive(center post) is the negative attached to the outside of the can and attached to the chassis if so where can I attach the negative?Thanks Doug
[Image: http://i1095.photobucket.com/albums/i474...hoto01.jpg]
#2

(03-06-2012, 09:01 PM)fixinmyphilco Wrote:  Ok This one has 2 can caps one is 12 mfd @450v the other is 4 mfd @450V In the picture below the cap in green has a negative lead and the center is for positive but the one in red seems to only have positive(center post) is the negative attached to the outside of the can and attached to the chassis if so where can I attach the negative?Thanks Doug
[Image: http://i1095.photobucket.com/albums/i474...hoto01.jpg]

That's because the one circled in red is grounded to the chassis and the one circled in green has a floating ground. This was a very common practice in 1930s radios, the reason they would do this is so they could install a fixed bias network between the center tap of the high voltage winding and the chassis.
Regards
Arran
#3

So if I rebuild the can I can just make sure the negative lead is touching the outside of the can or if I by-pass it the negative would just connect to the chassis perhaps where the paper cap next to it there connects to the chassis?
(03-06-2012, 09:20 PM)Arran Wrote:  
(03-06-2012, 09:01 PM)fixinmyphilco Wrote:  Ok This one has 2 can caps one is 12 mfd @450v the other is 4 mfd @450V In the picture below the cap in green has a negative lead and the center is for positive but the one in red seems to only have positive(center post) is the negative attached to the outside of the can and attached to the chassis if so where can I attach the negative?Thanks Doug
[Image: http://i1095.photobucket.com/albums/i474...hoto01.jpg]

That's because the one circled in red is grounded to the chassis and the one circled in green has a floating ground. This was a very common practice in 1930s radios, the reason they would do this is so they could install a fixed bias network between the center tap of the high voltage winding and the chassis.
Regards
Arran





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