[Elecraft] Astron RS-35M Hum

[wb6rse1 at mac.com]

Here's the resolution to my Astron RS-35M Hum issue.

First my thanks to all who replied on and off list. 

With the transformer isolation pads installed the hum was noticeably reduced and did not change with load. But it was still noticeable. So I looked at the bridge rectifiers to see what was required to change them and discovered that one of the six connections had never been soldered!

The only hum now on this 5 year old PS is low level and you have to put your ear to the cover to even hear it. It's the same as my never-hummed 14 year old unit if you put your ear to the cover.

It appears that inspection/QC missed this one.

Consider the thread closed.

73 Steve WB6RSE