[Hallicrafters] Hallicrafters Digest, Vol 74, Issue 24

[james.liles]

Good morning Byron:
Aligning the 50.75kc I.F. will fix the problem.  Your SX-100 has all of the 
upgrades and will perform as if it included a product detector.  The BFO 
will leak backward into the AGC detector if the 50kc I.F. is aligned to 
50.5kc --- that is the primary reason for moving to 50.75kc.  There is a 
complete note in the Hallicrafters archives regarding the SX-100 model and 
enhancements issues.  --- Kindest regards Jim K9AXN

Original message:


> Hello-
> ??? I have just finished replacing the paper capacitors with some good 
> mylar types, cleaning switches and tube sockets,?installing test select 
> tubes?and checking resistors with an ohmeter checking for ones that 
> shifted value. A lot of laborous cleaning with small rags and windex, I 
> went ahead and removed the front panel to gain better access to cleaning 
> and replacing capacitors. This is a pretty nice unit that doesn't appear 
> to have been messed with any at all.?Have brought up the SX-100 (Mine is 
> stamped a MK-IIA) and checking it out. I noticed the BFO is getting into 
> the AVC and it increases the S-Meter upward about 2-3 S-Units. I want to 
> burn-in the set good before I do the alignment, but wanted to ask: Will 
> the BFO leakage decrease when the IF alignment is done at the recommended 
> 50.75 KC? I verified my unit has the BFO updates (taking output from 
> plate), it has the 2-pole SSB/AM switch, and it has the pin #9 on V-7 
> grounded.
> ??? Any suggestions appreciated. As of now I am a little concerned as the 
> sensitivity seems a little low, but I have yet to do the alignment.
> ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? 
> ??? ??? ??? ??? ??? ??? Thanks, Byron WA5THJ