Field trial 302

[HarrySmith]

Dave, was there not an "F" number on it?

[poplar1]

No F- number, just serial numbers on the parts and on the CS-1 form.

[paul-f]

Paul, it's a 302, not a D-97464. July '37. No wiring diagram.

So is there a H1 mounting code on it or some other 302 marking?

[poplar1]

Reply #4:

Housing                                8224   
(H1 outside over mouse hole)

It's like the "new" 6-37 set discussed here recently, except for the grooved handset.

http://www.classicrotaryphones.com/forum/index.php?topic=10968.30

[Dan/Panther]

This appears to be in every way a production set and not a prototype. It appears to have all the same parts as any other 302 with small plungers. Only the Bell Labs serial numbers and Form CS-1 stand out so far. And perhaps the 6/37 date for a grooved F-type handset.

It may be possible, it matches the production models, because they got the design correct the first run. In the case of the 500, they may have had to beef up a lot of the internal parts, that's why the difference.

D/P

[poplar1]

Here are some pictures.

[poplar1]

More pix:

[poplar1]

Only clue on the outside was the serial number 8224 near one of the back feet:

[Mr. Bones]

     That is certainly one of the most interesting 302 sets I have ever seen! How great to have the Bell Labs form, etc. A well-preserved piece of telephony history. Congratulations, and enjoy!

Best regards!

[poplar1]

Here is another field trial 302 (not D-97464) that sold 2015-04-19 for $255. The serial number for the Bell Labs Trial on Form CS-1  is #8121.
(Ebay link: http://www.ebay.com/itm/RARE-1937-Field-Trial-8121-Western-Electric-phone-302-TELEPHONE-Parts-/161667865400)

Part:           Date:            Serial Number:
Bell Labs Form CS-1              8121
Baseplate      7-37                 8121 (stamped outside by back foot)
Ringer          4/41 red stripe (not original)                 
Ind. 101A     II 37                 8121
Capacitor        ?

Housing                                   
H1 outside over mouse hole for mounting cord); separate entrance for handset cord; vented hand hold

Dial: 4HB      III 37
#plate: 149B III 37
Brass finger wheel
Black dial adapter (gasket)

H3C Handset cord-- H3C   IV 37
Fabric jacket, rubber covered conductors                       

Mounting cord-- DP3   III 37 [possibly D3P rather than DP3??]
Fabric jacket, rubber covered conductors

F1 Handle    6 03 37
(GROOVED--- Seller states that the "seam" may have been one of the features for the field trial. A production set from 7-37 recently found has an original grooved handset.)

F1 xmtr unit  6/37     7961           

HA1            7-15-37 

Xmtr. cap     6 11 37

Rec. cap      6 12 37             

[Doug Rose]

David...in your opinion, why did WE go from a solid hookswitch cover in 1936 to a vented cover in 1937 and back to a solid cover. Makes no sense to me. I am just asking, not rocking the boat....Doug

[unbeldi]

I would suggest that the "vent holes" were really sound holes to improve the quality of ringing, as the thick metal shell would significantly attenuate the overtones that provide the character or quality of the ringing gongs.

I believe earlier prototypes had entirely different sound holes in the bottom plate.

Was this last exhibit the one with closed cradle?    The ringer in this phone has been replaced, so it is entirely possible that the cradle closure and hookswitch assembly might have been replaced too, so no one can be sure how significant these variations really are.

[unbeldi]

F1 Handle    6 03 37
(GROOVED--- Seller states that the "seam" may have been one of the features for the field trial. A production set from 7-37 recently found has an original grooved handset.)

I find it strange to believe that the grooves would make it desirable to field test the equipment.  The grooves resulted from a  significant improvement in the molding process, that reduced manufacturing time and cost significantly. It essentially automated the removal of the molding fins (the thin skins of plastic that form in the seam between the two mated parts of the mold) and eliminated polishing of the handle.

[poplar1]

David...in your opinion, why did WE go from a solid hookswitch cover in 1936 to a vented cover in 1937 and back to a solid cover. Makes no sense to me. I am just asking, not rocking the boat....Doug

Doug, I had assumed that all had "vents" until sometime in 10-37. Some of the last small plunger housings in 10-37 (and Kenton's 11-37 example?) did not have vents. The housings were redesigned (large plungers) on sets manufactured starting 11-37, and these don't have vents, so maybe they started using the newer unvented type cover on remaining small-plunger housings. Of course, there could be exceptions -- I do recall seeing a photo yesterday of a small plunger set without vents -- and I don't know if this was originally manufactured that way or updated later.

[poplar1]

I would suggest that the "vent holes" were really sound holes to improve the quality of ringing, as the thick metal shell would significantly attenuate the overtones that provide the character or quality of the ringing gongs.

I believe earlier prototypes had entirely different sound holes in the bottom plate.

Was this last exhibit the one with closed cradle?    The ringer in this phone has been replaced, so it is entirely possible that the cradle closure and hookswitch assembly might have been replaced too, so no one can be sure how significant these variations really are.

I didn't attach the photo showing the vents, but did include them in the list :
        Housing                                   
        H1 outside over mouse hole for mounting cord); separate entrance for handset cord; vented hand hold

I tried to attach the photo here (from the Ebay listing), but it failed the security check!

In any case, most of the small plunger sets (they were made from IV 36 - 11/37, but so far I've owned only 3/37 through 10/37) found as removed from service years later -- after many rebuilds and/or repairs -- have 6A dials and replaced ringers and cords. Yet, the "vented" covers usually remain on these rebuilt sets.