[Milsurplus] TMC AC line electrical hazard

[Nick England]

Howdy gang - I was reminded of an unpleasant fact of TMC life while
starting to resurrect a TH-39/UGT AFSK keyer so I can play RTTY with
my FRT-57.

*Some* TMC gear with military-type AC power cord connectors (3-pin
MS3102-16S-5P) are wired bass-ackwards from others !!

My TH-39 (TMC TIS-3) units have ground at pin C and AC line at pin B.
But most (all other?) military equipments with the same connector have
ground at pin B and AC line at pin C
Some TMC gear is wired this way too. e.g. MSR-3 has ground on pin C,
MSR-4 has ground on pin B

Obviously you can find yourself in serious trouble if you don't check
out each and every piece of gear/power cord.
Neutral and hot AC lines aren't specified in the power cord wiring so
it is 50-50 that you'll have a hot chassis if you mix a Ground_B cord
and Ground_C equipment.
I am re-wiring my TMC gear and anything else to consistently have
ground on pin B (and adding a note on the rear panel).
That way I can use the same power cord wiring on everything.
I dimly recall this might have been a field change on some mil TMC gear.

Just a word of caution....check that your line cord ground pin
actually goes to the equipment chassis.
cheers,
Nick K4NYW
www.navy-radio.com