[Hallicrafters] SX-42 progress and new postings

[Craig Roberts]

Holy mackeral! --  those ladies in Chicago sure used a lot of solder!

I've been asked to keep y'all posted on my SX-42 restoration, so here's 
the story thus far:

The best news is that my bandswitch is in perfect shape -- not a hint of 
undue heating. What a relief!  I'm almost half-way through the recapping 
and resistor replacement phase. Now, I'm one of those anal types who 
insists upon stripping out old components completely -- down to the 
terminal -- whenever physically practical and whenever it doesn't pose 
an undue threat to other components. The SX-42's pretty rugged with big 
ole, honkin' terminals, so that's not a problem with this radio. The 
practice is very time consuming, though. A lot of the labor is expended 
wicking huge gobs of original solder off the connections. I truly 
believe one of the reasons our Hallicrafters boatanchors are so heavy is 
because of all the lead wasted on the factory solder joints. Okay, I 
don't really truly believe that, but you get my drift. How else can you 
explain how my neatly soldered Collins 75S-3 is one-quarter of the 
weight of my SX-42, hmmmm?? (I suppose it could the absence of a 
45-pound power transformer, 103-gang tuning cap and cast iron chassis).

I'm very fortunate that the radio has been largely unmolested. 
Replacement of the power supply electrolytic with separate caps and the 
substitition of one coupling cap seem to be the only repairs done to 
this set during its history. This makes life a lot easier now. As you 
know, it's a lot harder to work on a radio that's been "repaired to 
death." 

Even in this early stage of restoration, the SX-42 plays strongly on all 
bands -- including FM -- and the audio is superb.  The only "glitches" 
are a very wobbly BFO("C-C-C-QQQ-Q") and dental pain inducing overload 
on very strong signals. I expect to cure the latter problem as I finish 
recapping the AVC line, though the 50KW BC station at 1500 KHz a half 
mile from my house may still be problematical. I must say, the radio 
demonstrates astounding sensitivity (as is often the case with single 
conversion sets).

As others who've  restored the SX-42 have noted, a fair number of 
resistors are out of spec -- mostly wildly high. But, that's to be 
expected with old carbon composition devices.  The "bulletproof" micas 
of this vintage are also starting to fail, so those repairing units from 
the 40's and 50's can no longer assume that the "postage stamps" will 
still carry the mail, so to speak.

I am grateful to several friends who've helped with this project so far. 
I've gotten much wonderful advice and encouragement, skillfully rendered 
wiring diagrams, details of updates and mods, beautiful and inspiring 
photographs and offers of other aid.  And thank you to the previous 
owner, a list member, who represented the radio accurately and priced it 
fairly (and packed it well for shipping, too).

I'll continue my work over the next couple of weeks and let you know how 
it's going.

By the way, I've posted a new, cleaned up version of the original SX-42 
manual on my website. It's at www.aerialacts.com/Halli_SX42_manual.pdf . 
This file, besides looking much better, is a lot smaller than the first 
version I posted a few days ago. It's still a little over 14 MB, though, 
so please be patient when you click on it. Even with a broadband 
connection, it takes several minutes to download and display.

I've also posted a high-resolution, multi-page version of the SX-42 
schematic at www.aerialacts.com/SX42_schem.pdf . It's the original 
factory schematic enlarged and broken into eight, labeled  8.5 x 11 
pages. This document makes the component values actually readable (!) 
and can be printed conveniently. It's about 3.5 MB in size.

Again, if you'd like hard copies of these documents, please ask. I'll be 
happy to send them to you free of charge.  It's a way of saying thanks 
for all the help and friendship I get from members of this group. 

73,

Craig
W3CRR