[attachment=6620][attachment=6620][attachment=6620][attachment=6619][attachment=6619]I am restoring a Philco Jr Model 81. When I got this radio, I found a wire that was connected to the Oscillator Coil (fig 12 on the schematic) and the other end was taped off with tape. This is my first experience with a radio made in the 1930's and I can't determine where that wire should be connected. Along with the mystery wire (black), resistor #10 and Capacitor #5 in parallel are connected to the same lug as another black wire that goes to the Det Oscillator Tube #77. I have included a photo of the wire which I have put a green shrink sleeve for identification.
If someone has one of these radios on the bench, I would appreciate any help identifying where the mystery wire should be connected to. I have the radio recapped, resistors replaced that were out of toleranc and the radio does work, although the sound is somewhat distorted. It could be caused by this wire as is part of the oscillator circuit.
Welcome to the Phorum Jay!!! I edited your post to add a link to the schematic to assist folks in answering your questions if you continue this thread.
The gimmick wire that morzh mentioned is labelled A in the schematic. You can see more about it in this post on improving an 80 (it is labelled A in this article) and its just a diagram of a wire connected at one end in this second article.
(03-02-2015, 09:07 AM)klondike98 Wrote: Welcome to the Phorum Jay!!! I edited your post to add a link to the schematic to assist folks in answering your questions if you continue this thread.
The gimmick wire that morzh mentioned is labelled A in the schematic. You can see more about it in this post on improving an 80 (it is labelled A in this article) and its just a diagram of a wire connected at one end in this second article.
Thanks much. I reviewed the article and found it very interesting. Thanks for adding the schematic. I thought about that after I posted this problem. It was strange to see a piece of dirty white tape that looked like the old adhesive tape used for bandaids years ago wrapped around the loose end. My radio has lots of volume on strong stations, in fact, so much that I can not cut the volume down to zero. Just the same problem everyone else has with this radio that I have read about in the Phorum.
(03-02-2015, 09:59 AM)morzh Wrote: Yes, it is twisted, look at the links Klondike gave you.
Thanks morzh. I have read the links. My comment should have been that the loose end of the wire does not physically connect to a lug somewhere. I will add some wire and do the wrapping and see if that helps. I have already replaced the 4 meg resistor with a 2 meg as mentioned in the Service Hints.
Here's a photo of the underside of an 80jr after restoration. You can see the gimmick wire twist just above the blue tip of the large brown dogbone resistor.
[Image: https://dl.dropboxusercontent.com/u/54621529/80_6_a.jpg]
You guys are great! Thanks for the photo. That really helps. I can rest easy now knowing the loose wire has a purpose. I will make the wrap as in your photo.
(03-02-2015, 12:34 PM)Bill Bacco Wrote: If you are interested in some changes I made to my 81 Jr to address the volume issue, check out the following thread.
If you don't have the set connected to a good ground the volume control won't work properly. It's designed to shunt the rf energy from the antenna to ground as you turn the volume down.
Terry
(03-02-2015, 05:16 PM)Radioroslyn Wrote: If you don't have the set connected to a good ground the volume control won't work properly. It's designed to shunt the rf energy from the antenna to ground as you turn the volume down.
Terry
Hi Radioroslyn:
I understand ground, and there are two types, house ground and earth ground with a driven ground rod. Can this be safely connected to the screw holding the receptacle plate on the wall which is a grounded screw? I don't want to trip a breaker or GFI.
