09-07-2015, 12:55 AM
I'm working on resurrecting a very neglected 37-11. Finally got it re-capped, re-resistored and mechanically functional again after much de-rusting, cleaning and scrubbing. As you can see in my other posts, I also had to rebuild the set's rock-hard flexible coupler. The set's output transformer had an open primary, but everything else electrically looked good. There were 9 bakelite blocks in this set to melt out and restuff. Quite an undertaking, especially since the wiring to these blocks tends to be very crowded and dense. Anyway, the initial power-up brought static on all bands, but no apparent signals, even with a 60' long wire antenna up about 30 feet.
Since I had disassembled the main tuning capacitor and the mica-trimmer capacitors for cleaning, I figured it would be best to start off with a quick effort at alignment. The IF alignment went without issue, and the set was only slightly off in that regard, but when I started doing the RF portion of the alignment, I was befuddled to see a completely different RF section configuration staring back at me than what's depicted in Riders volume 8 for this set (pages 8-13 to 8-16 in the Philco section). The Rider's shows 3-section compensators for the Osciallator, Antenna and RF sections of the RF chassis. As you can see in the pics, my radio has a different layout. Mine is a Code 125 chassis. Is it possible the Riders information is showing procedures for a code 121 chassis? If so, does anybody have info/procedures for aligning my set? Thanks in advance for any thoughts on this. Oh, by the way, the first step of RF alignment has you inject a signal at 18MC, and I was able to hear that signal, but it was a little weak.
Before:
[Image: http://www.martinihenry.com/temp/37-11x/beforesm.jpg]
After:
[Image: http://www.martinihenry.com/temp/37-11x/after.jpg]
RF Subassembly underside…
[Image: http://www.martinihenry.com/temp/37-11x/rfchassis.jpg]
What Riders says I should see…
[Image: http://www.martinihenry.com/temp/37-11x/riders.jpg]
It's my code…
[Image: http://www.martinihenry.com/temp/37-11x/code.jpg]
Since I had disassembled the main tuning capacitor and the mica-trimmer capacitors for cleaning, I figured it would be best to start off with a quick effort at alignment. The IF alignment went without issue, and the set was only slightly off in that regard, but when I started doing the RF portion of the alignment, I was befuddled to see a completely different RF section configuration staring back at me than what's depicted in Riders volume 8 for this set (pages 8-13 to 8-16 in the Philco section). The Rider's shows 3-section compensators for the Osciallator, Antenna and RF sections of the RF chassis. As you can see in the pics, my radio has a different layout. Mine is a Code 125 chassis. Is it possible the Riders information is showing procedures for a code 121 chassis? If so, does anybody have info/procedures for aligning my set? Thanks in advance for any thoughts on this. Oh, by the way, the first step of RF alignment has you inject a signal at 18MC, and I was able to hear that signal, but it was a little weak.
Before:
[Image: http://www.martinihenry.com/temp/37-11x/beforesm.jpg]
After:
[Image: http://www.martinihenry.com/temp/37-11x/after.jpg]
RF Subassembly underside…
[Image: http://www.martinihenry.com/temp/37-11x/rfchassis.jpg]
What Riders says I should see…
[Image: http://www.martinihenry.com/temp/37-11x/riders.jpg]
It's my code…
[Image: http://www.martinihenry.com/temp/37-11x/code.jpg]
