WE 297G subset re-wiring

[Sargeguy]

I came across a nice early Western Electric Company 297 G subset a while back marked "Southern Massachusetts Telephone Company".  I focus my phone collection on RI phones (SO MA TELCO served parts of RI and the MA South Coast) so I am anxious to get this up and running.  So far I have tried it wired to the outside line with red-L1 and green to L2, and reversed it.  I get tone but no ring.  Ringer and coil test OK.  I could just untie the wiring harness and rewire it as a 295A bypassing the ringer, but before doing so I am open to suggestions for a more "holistic" method of getting it to ring, or the least intrusive.  Here is the schematic, the phone is wired the same way as far as I can tell.

[unbeldi]

what kind of desk stand or set do you have connected to it?

[Sargeguy]

I attached a 229 deskstand to test for tone.  I have detached it and I am trying to get the 297G to ring on it's own.  I am looking at the 4 different ringer configurations shown on the schematic and trying to figure out which one I have. 

[Sargeguy]

Black ringer wire Z has continuity with L2
Red ringer wire has continuity with GND

[unbeldi]

If this is the way it is wired, then indeed you wouldn't get ringing between L1 and L2.  It's the wiring for grounded ringing, or party-on-ring, which means it is ringing between Ground and L2.
For bridged ringing between L1 and L2, you might want to connect the ground terminal to L1 or move the red ringer wire to L1, and move the black ringer wire behind the condenser.
But the coolest way is to construct a party line the way it was intended in the 1910s.

[unbeldi]

The 297A (or 1297A) was for four party selective central battery service.
2500-ohm biased ringer, relay and inside binding posts
Cost according to 1908 Catalog $9.15
Includes: 1 No. 8-BG ringer, 1 No. 21-D condenser, No. 20 induction coil, I No. 85-B relay.

You have the G version, but clearly it's for the same type of service. You have to figure out what the G difference is. Perhaps the extensions bell connections?

Do these components match yours?

[poplar1]

Relay probably operates only when bell box is mounted vertically.

[Sargeguy]

The 297A (or 1297A) was for four party selective central battery service.
2500-ohm biased ringer, relay and inside binding posts
Cost according to 1908 Catalog $9.15
Includes: 1 No. 8-BG ringer, 1 No. 21-D condenser, No. 20 induction coil, I No. 85-B relay.

You have the G version, but clearly it's for the same type of service. You have to figure out what the G difference is. Perhaps the extensions bell connections?

Do these components match yours?

I have a 1000 ohm un-biased ringer, and No. 46 coil otherwise they match.

You may be correct about the extension bell.  There are a series of of six old holes towards the bottom left marking where the original binding posts were located before being replaced, with new holes drilled in the process.  There are now eight posts, so two were added.

I have not had a chance to try out your suggestion yet.  It is my first New Year's resolution.  poplar1, the relay moves while horizontal, although I'm not sure that counts as "operating".

[Sargeguy]

I removed the internal wiring in order to clean the inside of the box, which was a little more filthy than the outside would lead you to expect.  After cleaning everything I placed it all gently back in the box, but snapped off the green wire at the condenser while trying to screw down the condenser.  I wrapped the wire so it would conduct.    I then switched the red ringer wire (to L1) with the black ringer wire (to GND) and ... nothing.  Since the green wire was broken off I disconnected it an used the Condenser bypass tool between L2 and GND and...it worked!  I tried a 1uF/250v capacitor between L2 and GND and see if that would get it to ring without any additional butchering of the old wires, but it didn't, so I switched to a big banana colored 2uF/250v.  Now if I lean it to one side to side the ringer cuts out.  I'll have to make sure I screw this one to the wall. 

[unbeldi]

The 297A (or 1297A) was for four party selective central battery service.
2500-ohm biased ringer, relay and inside binding posts
Cost according to 1908 Catalog $9.15
Includes: 1 No. 8-BG ringer, 1 No. 21-D condenser, No. 20 induction coil, I No. 85-B relay.

You have the G version, but clearly it's for the same type of service. You have to figure out what the G difference is. Perhaps the extensions bell connections?

Do these components match yours?

I have a 1000 ohm un-biased ringer, and No. 46 coil otherwise they match.

The ringer properties you found are a bit surprising and would mean that this subset was not actually used on a 4-party selective ringing line, as intended. The polarized and biased ringer is needed to achieve error free operation when signaling any one of four parties without using coded cadences.

I think this makes this perhaps operate like a 295?

[Sargeguy]

Unless the bias spring just fell off, the bias spring adjustment screw is present.  I know they often removed it on un-biased ringers. 

[unbeldi]

Unless the bias spring just fell off, the bias spring adjustment screw is present.  I know they often removed it on un-biased ringers.

Ah, a ringer that would be advertised in a catalog as unbiased, would not have the adjusting screw.  So the ringer is actually a biased ringer, just not used that way. The textile threads used to hold and tighten the spring were so thin that it is not surprising they have been lost.

[Sargeguy]

I'll have to poach a bias spring from somewhere and see if that improves performance.  It rings, but it could be improved.