[Test-Equipment] TV-7x/U Electrical Hazard

[eric lemmon]

I have a TV-7A/U Tube Tester, Serial 4036.  Although this unit works
perfectly, I have always been annoyed by the fact that it had only a
two-conductor (ungrounded) power cord.  Even though I meggered the AC
primary to the chassis and found excellent isolation, the unit is definitely
not double-insulated, and should have a grounding (three-conductor) power
cord for safety.  I realize that, at the time these units were designed,
grounded outlets in non-industrial settings were quite uncommon.

It took me less than an hour to convert my unit with a grounding power cord.
I had to drill a 6-32 clearance hole in the front panel, between the power
switch and the line voltage adjust rheostat, but that was easy.  I removed
the paint on the underside of the panel around that hole, and used an
internal-tooth lockwasher to ensure positive contact between the ring lug
and the aluminum panel, with a dab of Noalox for good measure.  A
right-angle strain relief where the cord enters the panel replaced the
rubber grommet, and also made the cord easier to stow in the lid.

73, Eric Lemmon WB6FLY