[Hallicrafters] SX-42 Progress

[Rich Soennichsen]

Things are plodding along slowly with my SX-42 project.  The
re-capping is done and I am trying to bring the receiver up.
Luckily it is not working so life gets interesting, at least that is
what I keep telling myself.  This is my first time dealing with ANY
radio, the SX-42, trial by fire!

The lowpoint, pulling on a variable cap to replace a paper cap
underneath and pulling a switch contact right off the bandswitch. 
Horror!!  After I went for a walk I managed to surgically replace it. 
whew.

So far:

No audio output, no hiss, nothing.  Hooked signal generator to input
and get a nice tone, so audio section probably ok.

Local oscillator (7F8) oscillating.

Put my signal generator on the first IF and see nice amplification on
the plate.  This signal is greatly attenuated by the 2nd IF coil but
does make it to the grid of the second IF.

No I found no ouput on the grid of the 2nd IF.  Both 1st and 2nd IF
tubes are new.  Plate voltage is there, filament voltage is there. 
Here things stayed for two weeks while I poked and prodded and try to
understand what I am seeing.  (sorta)

This morning I wiggled the 2nd IF metal tube (for the umpteenth time)
and noticed that it was not as warm as the other metal tubes.  Putting
the original 6SG7 back in and I have output on the second IF plate! 
Yea!

still zero audio, booo...

The education continues.  I would appreciate hearing from anyone with ideas.

Thanks

Rich

KG6ZTC
http://members.cruzio.com/~soennichsen/sx-42