[Milsurplus] Cleaning-Up a BC-669 Modultor.

[David Stinson]

Working on a second Hallicrafters BC-669 
(this a -BM model and when I got it, it looked a lot
like a B.M.)  for an old friend who always wanted one. 
I got a pile of BC-669 goodies from a very
kind gentleman from Arkansas (thank you, Don) 
many years ago and recently was generously gifted
another ( thank you, Mike!) and that prodded me
into getting them going.  Have two on the air now.

I posted some photos of "before and after" of the
modulator deck on Novice Rig Roundup on Facebook.
Several people asked what I did and I thought it would 
be interesting to one or two folks here.

Here's is "before:"
https://goo.gl/photos/etZdrBobNiUGkrzE9

Here is "after:"
https://goo.gl/photos/qQATTDbyZxDopJ6C7

A short description of my procedure:

First, I am not a cosmetic artist and it will not look 
as good as the work of your friend who does 
complete cabinet restores.
It will be presentable, not perfect. 
But it didn't cost me $300, either.

Vacuum out any loose crud and mouse leavings. 
Remove the speaker, meter, nomen plate and 
wooden plaque. Save all hardware in its own 
container. 
Test Simple Green cleaner to make sure it won't 
damage markings- I've had no trouble. 
It's not a great cleaner but strong stuff like 409 
will damage markings and years later, 
give you green corrosion in cracks the rinse 
didn't reach.  Spray Simple Green all over and 
let it soak for a few minutes, then douche the rig 
down with a garden hose.
Let it dry for a day.  Naval jelly on the chassis 
and transformers to get rid of most of the rust. 
Any transformer that dies from this was terminal 
anyway. Follow with flat black rust converter primer
to prevent any further rust. Let dry completely.

Go over the chassis inch by inch and "tweak" all the
grounds.  I'm finding more and more Hi-Z ground points
causing all kind of troubles.  Usually a drop of 
De-Ox-It and a "tweak" of the bolt is all that is needed.

The front panel will still have a dingy, yellow brown, 
washed-out look from micro dust in the cracks that 
you cannot remove. Do not try to scrub it out- 
you will destroy the paint and the markings. 

Touch-up paint on the panel with flat black enamel. 
Let dry completely. Spray De-Ox-It where needed 
and leach a bunch of it into the front of any 
toggle switches.
IMPORTANT: Inspect, clean and lubricate any 
rotary switches before you start twisting them. 
I've seen switches destroyed by skipping this step.

Drizzle 3-n-1 Oil all over the panel and rub in 
with a soft bristle brush using swirlling motions until
you see an even sheen all over, coating the knobs
 as well. This will blend the paint touch-ups with 
the panel and darken the micro-dust, 
also blending it in. 
Do not scrub hard (this is the recommended treatment
 for black wrinkle paint in WWII Radio Maint. books).

Let sit for an hour or so, then wipe away excess with
a soft cloth. You'll have more excess to wipe off 
after a few hours.  Test and clean meter, speaker etc. 
Restore the nomen plate, plaque etc.
Reassemble and continue your electronic refurb.

I'm sure there are a hundred "better ways."
This works for me.

Here is 'first light" for the RF deck after finishing 
the refurb and alignment on the receiver:
https://goo.gl/photos/HvxKwpb1kxeJWAjK7

After fixing a bunch of unusual problems, the 
transmitter is outputting 55 Watts carrier plate-
modulated by FOUR 6L6s.  It sounds excellent.
Now to rebuild the second power supply.

And here are the two finished rigs on the bench:
https://goo.gl/photos/b33cpJ5oKfupKBT5A
The near rig is the -BM, the far is a -B.

For those who didn't see it before, here's
"first light" for the -B model:
https://goo.gl/photos/2PRa1aNi6E3veaQe8


GL OM ES 73 DE Dave AB5S