[Hammarlund] Meltdown!

[Robert Nickels]

The plan was, I'd pull my "old" SP-600 out of the nice Premier cabinet and
and install the "new" SP-600-JX17 that I picked up at the Princeton IL
hamfest last weekend in its place.   Except it wouldn't come out!   After a
few minutes worth of alternate prying and head-scratching I managed to break
it loose and pull the receiver out of the cabinet.   Only to find a *BIG
PILE* of black gunk on the bottom on the cabinet!   Enough to virtually glue
the chassis in place.

I knew the receiver emitted a bit of smoke and a nasty smell the last time
it was powered-up.  I suspected an overlooked black beauty had shorted and
taken out a screen resistor or something, but as it turns out it was
slightly worse.   One of the old caps had shorted alright, the 0.022uf right
across the B+ supply now measures 7.2 ohms.  Not enough to blow the fuse,
but enough to draw loads of current thru the last filter choke which in turn
got hot and discharged a massive amount of the TAR used for potting
material.   Tonight I pulled the chokes out and cleaned them up, and since
the windings measure OK I put things back together and everything seems to
be working just fine (after replacing the shorted cap, of course).

Question is, will the choke be reliable without a full load of tar inside?
I can't see why not (in the hamshack environment) but would appreciate any
comments on this.

Meanwhile the new JX-17 purrs like a kitten ;-)  But I think I'll check out
the cap situation before it goes in the cabinet.

73, Bob W9RAN