[Collins] Re: 30S-1 hot cabinet

[Stu Martin]

Re: 65vac between cabinet and ground.

I recall a recent thread stating that a possible schematic error exists with
the 240vac input wiring in the 30S-1. It was stated that the jumper across
terminal 3 and 4 is correct, but the jumper across terminal 2 and 3 is in
error. Collins Amateur Service Agency Bulletin 1015, dated July 30, 1965,
page 1 of 2, states "That a known problem exists with mechanical vibration
of the 30S-1 cabinet when wired to 220vac." Seems the power transformer's
magnetic field excites the cabinet. The fix indicated is to connect both
terminals 3 and 4 to terminal 2, neutral. Thus the reason for the schematic
change in the later manual. In addition, since three power transformer
variations were used in the 30S-1. It is possible that only one specific
transformer is involved. Not having a source of 240v available at this time,
I am not in a position to test this theory.

Stu Martin, k2qde