[Johnson] Johnson T-R Switch

[Charles Ring, W3NU]

I have three of these, with one good transformer and one good 6BL7 tube
between them. While replacing the power cord on the one I got running
again after many years, I also installed an internal fuse holder. I see
no sign that they ever had a fuse, not even the infamous fused AC plug.
Is this correct? What was Johnson thinking of to omit a fuse? Was the
transformer intended to burn out like two of mine did, hopefully with
the excess heat contained in the metal case? The normal working heat
around the 6BL7 is already enough to worry about even though the manual
says that is normal.

I'd like to get one more of these in working order. Any suggestions on
finding a transformer? The good one measures 425 VCT under load plus 6.3
filament winding, but i'd like the HV winding a little lower in order to
use silicon rectifiers instead of the 6X4. Also lower plate voltage
should reduce the operating temperature - losing some of the unit's 6dB
gain is acceptable, but i wonder if it's basic function would be
degraded too.

73 de W3NU