Hey, All,
'Been working on a (late) model 60, and I have all caps and all bad resistors replaced.
When I first got it running, it worked so-so, and after about 45 min the osc. quit completely, and found I had the classic coil problems that I've been reading about in this forum. Great info, BTW.
Anyway, yet more questions:
-- One member here thought that anything from 34 to 38 awg would work for rewinding the primaries on the osc and antenna coils. Ron, I know you have said that 38 is what you use. Any known problems caused by using 34? I would think that the issue is mainly one of getting enough of the turns onto the right place on the core, but I'm weak in my inductance theory. 34 is way easier to get in the time I have, and would like to do the rewinds either tonight or this weekend.
-- The secondary on the 2nd I-F coil (Item 25) measures 45 ohms instead of the 85 ohms shown on the schematic. Problem?
-- When the radio was working after the rebuild, adjusting the I-F trimmers too far one way would cause motor-boating to occur. Is this normal, or due to the above coil issues?
Thanks!
Scottie
Hi Scottie
Welcome!
Using 34G wire shouldn't be a problem at all. The key is to make sure you have enough turns if you don't the osc won't oscillate across the whole band. If memory serves me it won't oscillate at the low end of the band. The resistance the the IF coils shouldn't be a problem either as long as they peak at the IF frequency. With them not tuned on frequency it is very likely that it will break into oscillation.
Good luck
Terry
Terry.
Appreciate the insight. From my digging, 17 turns counterclockwise for the osc primany. Mine was so corroded that it was hard to tell. I just cleaned up the lower antenna primary last night and counted 7 turns clockwise for that.
Thanks!
Scottie
On the osc coil you can throw a few extra turns on to be sure it will work ok. If you wind it backwards just switch the connections after you find it doesn't work. # of turns on the ant coil is not critical at all.
Terry
I replaced the BC oscillator coil in my 37-60 with a toroid. Long story why but it worked like a champ.
Don't think I have a big enough bottle of aspirin for that.
Terry
exray Wrote:I replaced the BC oscillator coil in my 37-60 with a toroid. Long story why but it worked like a champ.
Sounds like a story for it's own thread. Makes me wonder how you got it to couple with the secondary. Interesting.
Well, worked until about 2:00am this morning (3:00 am when you count the daylight savings change), and got 'er done electronically. Just a few little cosmetic things to finish it up. 8)
I used one extra turn on each, just in case I needed the wire for adjustments. So, 8 turns 34 awg CW on the antenna, and 18 turns 34 awg CCW on the osc primary, and I was able to tune across the BC dial, CHU Canada came in easily on SW, and that's from inside a metal shed! Cool. After I was sure it worked well and could align it, I took the coils back out and sprayed them with a coat of lacquer. They should be good for another 50 years at least.
Sentimental Backstory...
This radio is for my father's birthday in May. He found this radio back in the 70's, thinking it was the same prized model as one he had as a boy in the late 30's, and he refinished the cabinet. Turns out that it was a model 38 battery version (same cabinet as a 60), and as a high schooler I tried to get it working and failed. A little later I got into old radios as a side hobby, gained experience on some other radios, guitars and amps, got an EE degree, had three kids, etc. I'm just now getting his radio working, using a nice model 60 chassis that I found recently. Time marches on...
So, a labor of love, but just wish I had done it years ago. He'll be 83 in May, is still very active, and likes to listen to ballgames on the radio in the summer.
I'm so glad to be getting this done. Thanks again for all your help!
Scottie
Since you told that story I'll tell mine since it is similar.
I was contacted by an old feller in England about refurbing a 37-60. He was in his 70s and had spotted a decrepit 37-60 on ebay and it was something he recalled from his early days and had to have. He had never touched a radio before so it was a 100% new learning experience. He re-veneered the ruined photo-finish, borrowed a digital camera and voltmeter (neither of which he had ever used before) and we were able to restore his radio via several months of email. Pictures and drawings indeed are worth 1000 words.
Anyway, his BCB coil was open so I sent him the one out of my radio. He sent me his defective one so I could repair it but it got lost in the shack clutter. I had been meaning to try a toroid on one of these sets so that gave me the opportunity. Wasn't difficult at all to rig up.
After all was said and done he wasn't terribly thrilled with what little could be found on AM-BC radio in the UK. Especially in a rural area. So I then sent him one of those little toy broadcasters that were so popular a few years ago and a batch of old OTR cassettes. Man, he was in heaven. I haven't heard back from him over the years. Last contact he was restoring an old telephone
It was one of my better old radio experiences and goes to show that with enough tenacity old radios aren't insurmountable even for a novice.
-Bill
Note from site admin: Sorry, but the photos which were attached to this post are no longer available.
Man, you do have tenacity, to work a novice through all that. Great job!
Not much on AM in the UK? Not sure about Puerto Rico, but here I think we have three "music of your life" type oldies stations on AM, so it works out pretty well for listening.
On this one, for me the main issue was not one of doing the winding, but getting the right info together, and that's where this forum really helped.
Finding mylar/polyester tape retail was a hassle, too. Couldn't find it anywhere retail -- probably would have to go to Mouser or Newark. Weird, too, in that I work for 3M, and they have a whole commercial line of mylar tapes, but I still couldn't find any. I ended up using some old 3M varnished cambric tape that I found in my tape bin, should be fine.
Scottie