37-116 Restoration - Printable Version
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RE: 37-116 Restoration - 462ron - 02-11-2019
From what I've read in the past, band #2 oscillator coil is often found to be bad on the 37-116, I know mine was!
Ron
RE: 37-116 Restoration - rfeenstra - 02-11-2019
Didn't want to hear that!!! I had resistance checked all the coils and they seemed ok. That will necessitate disassembly of the tuner chassis again. What a pain! Oh well. Part of the process, part of the fun!
RE: 37-116 Restoration - Nathan Slingerland - 02-11-2019
Same on my 37-116. It's annoying but I don't honestly miss it that much in terms of listening.
RE: 37-116 Restoration - Ron Ramirez - 02-11-2019
You haven't lived until you've had one of those RF units apart a dozen times or so trying to chase down an intermittent (or otherwise) defect.
I don't think I'll ever buy a multiband 1937-38 Philco again.
Some of them look really great...but the RF units are too much of a pain. For me, anyway.
RE: 37-116 Restoration - rfeenstra - 02-11-2019
Ron, you're so encouraging! Looks like I'll be in the process of getting a life as it is the oscillator coil. I thought I checked that but maybe it went bad in the process of getting things back together.
Nathan, I thought about just leaving it as there isn't much there to listen to. However, there are couple of stations that I do occasionally listen to on the upper end of the broadcast band and need that range to get them. Besides, I'm this far and want the whole thing to work. So, the unit will come out and the coil removed and rewound. I rarely back away from a challenge.
RE: 37-116 Restoration - Ron Ramirez - 02-11-2019
Sorry, just being honest.
There have been several times when I have checked those band 2 oscillator coils on the bench, they checked good for continuity, only to fail to oscillate when everything was hooked up and powered on. Replacement is usually the only solution. There used to be someone who could rewind those coils. I never could successfully rewind one. I'll bet Brenda D. could; Mike (morzh) also.
RE: 37-116 Restoration - Phlogiston - 02-11-2019
As I recall they are only 33 turns - that is 11 X 3. I have yet to find one that was good.
RE: 37-116 Restoration - rfeenstra - 02-11-2019
Well, it will come apart this afternoon. Sounds like it may be a challenge!
Russ, have you rewound one of these?
RE: 37-116 Restoration - Kenradio - 02-11-2019
Hopefully you can rewind the band #2 coil. I was lucky in that the band #2 oscillator coils are good on my 37-116 & 37-690---there is plenty of activity on band 2 such as WWV, CHU & amateur radio transmissions + the upper part of the AM band (at least in my neck of the woods) Ken
RE: 37-116 Restoration - 462ron - 02-11-2019
I've never rewound any coil before but I gave this 37-116 a shot. Took me three attempts to get it to oscillate. I can get the low end and high end of the dial to work with alignment but the center in between goes deaf, it's not tracking well. After listening to this SW band on other radios, I saw where there wasn't anything much on it anyway so I let it be. Wasn't worth the hassle of taking that tuner apart a fourth time! Good luck with yours!
Ron
RE: 37-116 Restoration - rfeenstra - 02-12-2019
Success! There were multiple breaks in all three tapped sections of the primary part of the coil and a couple of breaks in the overlying coil. I thought sure I measured this coil but I don't think I did. Although, before removing the coil, I had continuity on a couple of the sections, but by the time I got the coil out, they were open as well. I must have counted 1 or 2 windings too few somewhere as I needed to add a tiny bit of capacitance to one of the compensating caps to get the dial lined up. Works great!
RE: 37-116 Restoration - Ron Ramirez - 02-12-2019
Congratulations! Great job!
Now please tell us how you did it. Wire gauge? Number of turns? Winding direction?
You may encourage me yet to try again...
RE: 37-116 Restoration - rfeenstra - 02-12-2019
Thanks Ron! I used 35 AWG wire. Both windings are wound clockwise looking at and starting at the terminal end. My counting gave 13 turns between terminal 1 and 2, 14 between 2 and 3, and 11 between 3 and 4. These numbers and 35 AWG wire produced resistances as listed on the schematic. The secondary was also 11 turns and is wound over top of the section of the primary that is between terminals 3 and 4. I don't know if that is important but that is how the original was wound. You can see on the pic of the finished coil the direction of the wind - clockwise.
As I said, it is possible that the first winding should have been 14 rather than 13 since I had to add 100mmf to the compensating cap #42C to get the dial lined up. Or, the wire spacing was different as when I measured the original wire, it indicated that it was 36 AWG, which I didn't have. Prior to adding the cap, I couldn't adjust 42C tight enough to get the low end of the dial on the right freq.
I'm thrilled that it worked cuz I didn't want to take it apart again!
RE: 37-116 Restoration - Phlogiston - 02-12-2019
Good (so I was close).
I would suggest that anyone doing a recap perform this rewind 'caus you are going to need it sooner or later.
I have a spare chassis for my 37-116 all done and ready to go. It came from the radio that had cracks on the right and left radius.
RE: 37-116 Restoration - Nathan Slingerland - 02-12-2019
I am so impressed that you rewound that coil! Awesome job.