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Mains power transformer on S5 K-12 kit hums?

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Hello all, I've been greatly enjoying my S5 amp setup, with one exception: just recently the mains power transofmer has started to hum. When some pressure is applied to the yellow taped portion where the 2 main power leads enter the transformer, the hum goes away, but then it eventually comes back. Is there any thing I can do to prevent / stop the hum? Will I need to replace the mains power transformer? Because its a sin when the amp sounds crystal clear with no extraneous noise or hum and then the power adapter starts humming at a low volume.
 
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Make sure the tranny frame is well screwed down beit shrouds or chassis to avoid the outer laminations buzzing. If the noise is coming from a loose E in the internal core, the only remedy is to dismantle unit from chassis, take covers off and drop the whole tranny it in a tin of polyuothane varnish and leave overnight.
Failing that a new tranny and hope.

It is a common dilemma; many tranny manufacturers use that yellow helf healing tape for the windings and when tranny finished assembled, simply do 2 dips in the varnish tank then leave to air dry without windings being properly impregnated. Vacuum impregnation is the compliance method which completely soaks every winding and core. A core made under this method is hell to split the laminations.

richy
 
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