[Elecraft] KPA500 cabinet buzz

[Andy Durbin]

"The KPA-500 transformer should be more than just a "hair" away from sides (step 6 above) as there are rubber bumpers and a ribbon cable between that should NOT be pinched. "

Over the production life of the KPA500 the transformer design, and perhaps the supplier, have changed several times.  The transformer supplied with my kit was significantly larger in diameter that the one shown in the assembly manual photos.  The only way I could ensure clearance was to shim the transformer before tightening the bolt and remove the shims afterwards.  There is very little clearance, perhaps 2 cereal box thicknesses, but I didn't record the shim stack.

Andy, k3wyc