[Kevin57]

Hi! I recently acquired the above named radio off Ebay. I've recapped it and replaced the rubber tuner mounts that were toast. But unfortunately, the previous owner had cut the speaker wires and shipped me completely different 5 inch pm speaker??? Luckily, I have a Philco S-21 speaker sitting around from a junked radio years ago which should work according from what I found on the web that can replace the original S-7 speaker. My problem is there is 3 wires coming off the speaker/output transformer and I'm uncertain which wires go where. The wires coming off the radio seem to be correct according to the schematic. One wire is coming from the + side of C53, one wire on the + side of C56, and the final wire coming off of pin 3 of the 6F6G. The 3 wires coming from the speaker were cut right at the hole(wasn't me) on the metal cover, covering the transformer. Two wires come off the outside terminals of the transformer and the 3rd wire comes of the right side terminal on the inside of the transformer. The schematic isn't very clear to me and the wires lack any insulation, hence no color codes to follow. I read somewhere that is not a good idea to apply power to the radio without a speaker connected, so I don't want to take any chances even though I'm eager to get it going! Does anyone know where the 3 wires connect in conjunction to the 3 wires I have have coming off the radio? Any information would be greatly appreciated!!!! Thanks!!!

Kevin

[OZ4]

Hi Kevin welcome to the forum.
This speaker wiring should be an easy one.
First is the wiring for the field coil going to the metal box intact? If so then the white wire is the one common to both the audio primary at 400 ohms and the filter choke for the power supply at 1140 ohms. The other two should fall into place according to the resistance readings from the common point.

You should be posting this link to make it easier for anyone helping. See here. http://www.nostalgiaair.org/Resources/209/M0013209.htm

[Kevin57]

Hi! Thanks for the quick reply! The wires underneath the metal cover are there but are not long enough to reach out through the hole. Also there is no insulation on all three, so no colors to go by. I have the 3 wires coming from the radio which are correct, but don't know which 3 terminals to solder to on the speaker assy.

[Raleigh]

From the schematic, it looks like the field coil terminals on the speaker/output xformer assembly should have 1140 ohms between them. Find those two terminals with your ohm meter. Call them terminals #1 and #2, just for reference. Call the other terminal #3. Connect #3 to pin 3 of the 6F6G tube.

Between terminals #1 and #3 should read either 400 ohms or 1540 ohms. If it reads 400 ohms, then connect terminal #1 to the + side of capacitor 53 (8 uF) and #2 to the + side of capacitor 56 (12 uF). If it reads 1540 ohms, reverse the 2 capacitor leads (#1 to 56 and #2 to 53.)

If terminal #1 to #3 doesn't read near either 400 or 1540 ohms, then something is wrong in either the field coil or the xformer primary or one of the connections to them. Just for fun, measure between #2 and #3. You should get the opposite reading as #1 to #3.

I've never seen one of these; I'm just going by the schematic and assuming from what you said above that the output xformer is mounted on the speaker, not inside the chassis. If that's wrong and the xformer is inside the chassis, then what I wrote above won't work.

Once you have it wired, check it by measuring resistance between + of cap 53 and + of cap 56. Should be 1140 ohms. Between cap 56 and pin 3 on 6F6G should be 1540 ohms. Between cap 53 and pin 3 of 6F6G should be 400 ohms. Between 53 and 6F6G pin 4 should be a dead short, and between pins 3 and 4 of 6F6G should be 400 ohms.

[Crist Rigotti]

Kevin,
Here is an answer to your PM.

It shows the 3 wires on my 60B speaker. The brown looking wire is actually the white wire on the schematic. You can also clearly see the withe/green wire.

Hope this helps.

[Image: http://i1060.photobucket.com/albums/t458...npwxel.jpg]

[klondike98]

You can figure out which lug is which by measuring resistance across the lugs. One reading will yield the field coil value of 1140. Another 400 and finally the total 1540.