302 Question. What is it?

[Fabius]

Came across this while surfing eBay. Looks like a coil? It appears to be sitting on top of the capacitor. Is this a model different then 302? Thanks. Also notice the left gong. Is that a lead weight and if so what for?

[rdelius]

Not a 302.I think this is a 304 set. The cardboard covered object is a cold cathode tube.This set was designed for 4 party lines

[unbeldi]

The model number of this is a 306.  It should have a handset mounting code H5 on the housing.

The ringer for the 306 should be  low-impedance (2 x 1000 Ω) version of the B-type, with the model number B3A.  In the 306, the DC blocking of the ringing capacitor is accomplished with the electron tube, providing a very high impedance against ground on party lines, which provides better inductive noise protection than standard grounded ringing circuits. The 306, therefore, uses only a single-condenser unit, the 195C (2 µF), for the audio circuitry.  The rest of the circuit, other than the ringing part, is identical to the 302, including the use of the 101A induction coil.

The insert in one of the ringer gongs is a 101A gong attachment [BSP C31.208 June 54]. It provides some enhancement in volume of the gong. In this phone, the resonator is installed in the 41A gong.  If it were installed in the 41B gong, the center on the cover would be punched out, but it would be this one that is installed first, I believe.  The gong attachment was apparently made from various metals; I also have at least one in brass.

[Fabius]

Great information, thanks.

[unbeldi]

306 type sets may often be found having their electron tube removed, such as this pekin red set, currently in auction at http://www.ebay.com/itm/131536350260 .

The giveaway is the B3A ringer, clearly seen in the picture, but also the mounting code. I doubt that a telephone company would have installed it this way anymore in the 1950, without also changing its low-impedance ringer.  It appears the condenser has also been switched. If anything, it probably could only be used on clean, short loops, or for individual service.

The B3A ringer is converted from a B1AL, but having the same date as the base. It seems original, by 7/53 the set should have indeed a 6D dial (as of ca. May 1953), but the dial does have one mounting screw missing along with its rubber grommet and brass rivet, which appears suspicious as well.

This ringer just happens to have the resonator installed as well.

[poplar1]

When WE repair shop modified sets with B3A ringers for use on individual lines, they used a (KS) 1.0 uF ringing capacitor in place of the tube, rather than the 0.5 uF found in 302s/5302s or 304s/5304s. I doubt that the capacitor shown in the red phone was added by WE. Since this red phone is part of a larger collection, it may be that the seller or a previous owner decided to "improve" the set by removing the tube and adding the wrong capacitor.

Pictured below is George's 306 (H-5 telephone set mounting) converted to a 302 Special:
http://www.classicrotaryphones.com/forum/index.php?topic=8091.msg88472#msg88472

[unbeldi]

When WE repair shop modified sets with B3A ringers for use on individual lines, they used a (KS) 1.0 uF ringing capacitor in place of the tube, rather than the 0.5 uF found in 302s/5302s or 304s/5304s. I doubt that the capacitor shown in the red phone was added by WE. Since this phone is part of a larger collection, it may be that the seller or a previous owner decided to "improve" the set by removing the tube and adding the wrong capacitor.

Indeed, this was also my suspicion.  I don't think WECo made a dual-condenser of the right size in the round can of the 195 type. I think they used a separate condenser mounted in place of the tube, and I think these caps were actually from a third party source, with a KS number.

[Fabius]

Again, great info. So the one in my photo looks correct?

[unbeldi]

Again, great info. So the one in my photo looks correct?

The components seem fine.  I can't see any additional leads out of the condenser, red goes to C, and black should go to the dial, so it must be a 195C.

The set seems to be wired for one of the TIP parties, I think the positive one.  But there is a black piece of wire that doesn't look original, without spade tip and connecting L1 to (I think) ground.
I think someone tried, perhaps succeeded, causing the set to ring on a bridged-ringing loop.

The diagram I showed earlier was for the negative party on the RING side, IIRC.

[G-Man]

BSP-

2.09 The 306-type telephone set is for use with common
battery antisidetone 4-party selective, and 8-party semi-selective
services. It is similar to the 302 type except that it
employs the B3A ringer, 195C capacitor, and in addition, a
333A, 372A, or 426A electron tube.

2.10 When service is upgraded, the 306-type set may be converted
to a 302-type set by replacing the electron tube
with a KS-16023 capacitor. If the set employs a 333A. or 372A
electron tube, the same P-10C385 bracket assembly is used for
mounting the capacitor. If the set employs a 426A electron
tube, the P-348078 bracket assembly must be replaced by a
P-10C385 bracket assembly for mounting the capacitor. The
modified set will be equivalent to one low-impedance ringing
bridge.

[G-Man]

Photos from eBay auction showing KS-16023 Capacitor With Bracket.

BSP-

2.09 The 306-type telephone set is for use with common
battery antisidetone 4-party selective, and 8-party semi-selective
services. It is similar to the 302 type except that it
employs the B3A ringer, 195C capacitor, and in addition, a
333A, 372A, or 426A electron tube.

2.10 When service is upgraded, the 306-type set may be converted
to a 302-type set by replacing the electron tube
with a KS-16023 capacitor. If the set employs a 333A. or 372A
electron tube, the same P-10C385 bracket assembly is used for
mounting the capacitor. If the set employs a 426A electron
tube, the P-348078 bracket assembly must be replaced by a
P-10C385 bracket assembly for mounting the capacitor. The
modified set will be equivalent to one low-impedance ringing
bridge.

[G-Man]

Additional - KS-16023 Capacitor Description