[Milsurplus] R-390 with Hoffman Mod.

[James Young]

A pretty 1951 Motorola R-390 (non-A) followed me home from Fair Radio the
other day. It's in VG condition, works but needs some help. I think I'm
going to have to start at the antenna jack and work my way all through this
radio. It has an added toggle switch on lower left front with a nomenclature
plate. When turned on it seems to add about 20dB gain to the front end. The
plate reads as follows:

  RECEIVER INCLUDES
  MODIFICATION KIT
    M281( )/GR-390
HOFFMAN LABORATORIES, INC

The plate is black engraved plastic with white lettering. Does anyone have
pertinent information or documentation on this added "feature" which
comprises an additional small chassis behind the front panel in the vicinity
of the former headphone jack location?

Also, does anyone have the 7 and 9-pin tube pin straighteners that have been
removed from the back apron?  Thanks in advance.

73 Jim Young
W8MAQ