Wiring Variations on a theme.....

[Babybearjs]

OK, all you guys who like to play with phones! heres a good one for you! Take a good look at the schematics for a W.E. 307 and a W.E. 309 and tell me how to make the bell ring W/O a 426 tube.... both phone have the same componets.... so how would you fix these phones to ring on a POTS line.... more over.... what would you do to make the phone actually work on a POTS line?

[unbeldi]

I posted circuit diagrams for the 307 sets in another thread:  http://www.classicrotaryphones.com/forum/index.php?topic=10281.msg109274#msg109274

Here are the images again, downloadable version are better fetched from the original post.

For the 307 A, B, C, and D:


and for the 307 E, F, G, and H


The 307A and 307E are the manual sets without a dial, so all switches of the dial can be ignored in these diagrams and the lugs are instead terminated/bridged on the apparatus blank.

What kind of condenser does your set have?  The 307 came with a canned triple-condenser (387A), but the 309 only needed two capacitors, because it had the tube for ringing.  So you may have to add an extra capacitor for the ringer.

So, the answer to your question should be pretty obvious:  Red ringer wire to L1, black to (possibly added) ringing capacitor, other capacitor lead to L2.

[unbeldi]

The answer to your second question (what would it take to make it work on a phone line) is also fairly simple, because these sets are in fact designed to operate on common battery circuits, but needed the local talk battery because on very long rural lines the CO battery was too weak to produce sufficient audio performance, while it was still fine for dialing.

So, simply connect 2 or 3 cells to the BL and BK terminals via the blue and black mounting cord leads.
Connect the line to L1 and L2.

All 307s should have come with a 5-conductor mounting cord.  How about yours?

[unbeldi]

So how about some pics of your phone?
Always nice to face the subject of conversation.

There are two main varieties of these, other than being manual or with dial.
One version (A-D) has a three-conductor handset cord for an F1 handset, and the other (E-H) has four conductors with an F2 handset.

The F2 handset is needed because in the E, F, G, and H sets, the transmitter circuit is completely separated from the receiver circuit, so that one can run multiple of these sets from a common local battery supply that has a choke in front of each phone to suppress coupling between multiple phone's transmitters.

As you can see in the diagrams, there is no connection at the very bottom line trace. between terminals R and E, for the F2 version.

[Babybearjs]

well.... so much for good photography... I got some photos, but the picture of the induction coil didn't come out..... heres what I have.....and to the answer about making the phone run on a POTS line.... take the jumper off of "C' and connect it to "C" and "BL", then put a jumper from "BK" (on the terminal strip) to "RBK", that will enable the transmitter. the phone should work as designed now.... Mine does....

[Babybearjs]

here are the 2 phones, side by side... you'll notice on the inductors, one has the resistor, one doesn't.... also, sorry about the pics.... when I try to take a closeup, the flash ruins the picture... I'm almost about to bring out my flood light!  Oh BTW.... with all this technology in this phone (mainly the Capacitor) where in the world would the #426 tube fit?? I was looking at the base componets and I don't see anywhere to put a 426 tube...does anyone have any pictures of the 307 with a 426 tube in it??

[unbeldi]

There she is.  very nice.
The tube was mounted on a bracket fasted to the capacitor clamp screw, which positioned it horizontally above the capacitor.

You have the right capacitor too.

The difference in the induction coil is clearly visible.  Unfortunately, it is not clear enough to see the dates.  Earlier than 1941?
Would you mind reading the date on the induction coil (and on the base) and tell us?

Does your hand set have a four-conductor cord or only three wires?

[Babybearjs]

No the units are both 307's... no 426 tubes at all. as for the dates, I didn't check except for the newest phone, the date was never clearly stamped so, its illegible. as for the rest of the 307's in my collection, the late 40's. I don't know if any of them are from the 50's... but there might be 1 or 2... my camera doesn't do a good job up close.... the flash interferes.    anyway, you can see the difference in the induction coils... this is a first for me.... I always thought the 104 coil always came with the 330 ohm resistor on top.    as for the line cord, when the phone comes to me in decent condition, I can sometimes reuse the original 5 conductor cord, if not, then I reorder a 5C subset cord from OPW and use it. I use 4C and 6 C biscuit jacks on all my phones to make them modular. the original phones connected to a 42A and a 44A wiring block, so using the jacks in place of the original blocks keeps the look original, but the service modern. On the 307's I want to keep them convertible so if they ever need to be used a LB service they can... I know that they used to convert these to CB service by switching out the induction coil and taping off the extra wires... this practice was found in my first 307 that I got when I thought it was a 302... at that time, I didn't know they had a series of 302's (or 300's) and I soon discovered the different models.... now, all I need is a 305 for my collection!