[Hallicrafters] SX-101 MKIII

[Bill Gerhold]

I have a recent acquisition of an SX-101 MKIII receiver.  Looking at the
BAMA site,
SX-101 MKII, (a MKIII schematic doesn’t seem to be available), the first
conversion
oscillator tube is shown as a 12AU7A.  The MKIII I have here has a
12BY7A in this
position as marked on the chassis and that is what I found in the
socket.
 
My confusion is Chuck Dachis’s book indicates all the different
variations of the
SX-101 use the 12BY7A as the 1st conversion oscillator.  The only
mention of
differences between the MK1, MKII and MKIII is “Minor electrical and
cosmetic
changes” between the different versions of this receiver.
 
Apparently, the MKII tube complement is different from the MKIII at
least in this
instance.
 
Anyone have a service manual for the MKIII or anything to add to this
apparent
discrepancy.  Or am I making too much of this.
 
Bill (K2WH)