[Elecraft] KPA-500 Loud Hum

[w1ujr at mac.com]

Noted that my new amp is making a fairly loud humming noise when not under load, and a much louder hum when under full power. New thing, have not heard this before, power output still good, but noise is really concerning. Removed top, nothing loose, should I try retorting the xformer hardware or look elsewhere?

Cordially, 
Bruce J. HowesW1UJR
www.w1ujr.net 

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