[Amps] Alpha 77Dx Filament Mod Update

[Paul Christensen]

Quoting myself:

> "Thankfully, the fix is simple and doesn't even require removing a single
screw from these amps.  The chassis and neutral can be un-linked by cutting
a jumper at the Cinch-Jones power plug.  Then, the three-wire power cord is
replaced with a four-wire cord in a (L1-L2-N-G) configuration.  Now, neutral
and chassis ground are safely disconnected and meet NEC criteria."

What I failed to mention is that four-wire service must then be run from the 
serving load center into the shack and a new 4-wire outlet installed.  So, 
if you've got three-wire service (L1-L2-G) with no neutral running into the 
shack, changing that out to at least #10/4 can be a real job.  I did it a 
few years ago on a hot sunny day in Florida when upgrading the service 
through the attic.  Not one of my most pleasurable moments in life.

For the wall outlet, I went with a 30A isolated-ground Hubbell Twist-Lock as 
I had it on-hand.  No real need for the I/G model, especially if using 
plastic rework electrical hardware.

Paul, W9AC