Thanks for your responses! This SX-28 is far from stock and is
extremely over-sensitive. I bought it about a year ago to help me
compare wiring and performance to my 1st SX-28, but this one was so
modded up, it was no help. The radio works ok, though, but requires a
lot
of knob tweaking to make a signal sound good. I have to run the RF
gain at
4 or below. I used to think that was a good thing
until noticing all the cross-mod on 40 and 49 meters.
There is a 6SG7 where the 6AB7 1st RF ought to be.
This receiver also has a 6H6 installed where T5 used to be.(far rear
right)
There is a 2nd 6H6 installed next to T6 (where the stock 6AB7 used to
be)
So thats 2 6H6s! There is an additional switch on the faceplate for
the noise limiter,
and the original noise limiter pot was replaced with a switchless
type.
There is also a 6SN7 where the stock 6H6 used to be.
The 6B8 that was with T1(1st IF) has been replaced with a 6SG7.
(The 6B8 pentode wire in T1 has been removed.)
The S meter was replaced with one labeled "carrier" and has very fast
ballistics.
It does OK on SSB, but the BFO sometimes has a little warble.
Its been re-capped, but not the RF deck. The dial calibration is dead-
on.
If you have any thoughts as to what these mods were trying to
accomplish,
I'm all ears. In the meantime, I'm going to replace the hotter tubes
with the stock originals,
one by one, and see how that affects performance. I really wasn't
intending to do a
complete restore on this SX-28, having done one already, and have had
that thrill.
Thanks for your help!