Repair of Western Electric 7A Dial Rewind Spring for WE 500 Desk Set

[kka2446]

Howdy,
I have a WE 7A dial from my 2-51 WE 500. The white metal 'spring retainer' piece ( just below the spider washer )
has come free, permitting the return spring to release and unwind.

Can the return spring be re-wound to the correct tension and securely reinstalled ?   
If so, are there any instructions to set the number of spring winds aka return tension and how to do it ?

Thanks,
John   

[RotarDad]

This can definitely be fixed, John.  I wonder why the spring came off - I wonder if the 90- degree bend in the wire near the end broke?  The bend up allows the spring end the fit in a hole in the dial shaft assembly ( the white metal part in your description).  To reattach, you'll have to remove a few parts from the backside of the dial:

1) Remove the dust cover (2 screws)
2) Remove the contact wire assembly (2 screws)
3) Remove the nut/washer on the dial shaft large gear and remove the large gear.  Note: I think the center gear will come off without removal of the gear train.  If not you'll need to remove the 2 screws holding the frame and remove the gear train as a unit (don't remove the 3 frame screws).

Now the dial shaft will pull out from the front side.  You'll need to reattach the spring bent tip to the hole on the shaft assembly (or perhaps make a new bend if the original broke off).  Note there is a flange at the edge of the shaft assembly at the top on both sides to hold the first turn of the spring wire, in addition to the hole. Then you will reinsert the shaft into the hole in the dial casting. The lower part of the spring has another 90-degree bend to the inside to fit in a slot in the dial casting.  The early dials have 4 slots to choose from, later dials have only one - I'm not sure if 2-51 still had the four slots.  If you have four, you'll have to experiment a bit to get the right amount of spring return.

You'll want to insert the shaft and then wind up the shaft 2 turns past the "stop" in the dial casting.  Then you will reverse steps 1-3 above to reassemble.

There are some good pics of 7C and D dial here, which very similar to the older 7A.  One critical item is the position of the nylon pulse cam upon reassembly.

http://www.classicrotaryphones.com/forum/index.php?topic=285.msg195944#msg195944

[kka2446]

Paul,
Wow !   Thank you very much for your fantastic reply. I'll work on my dial following your instructions and report back.


John

[HowardPgh]

The spring popped off because the part that holds the fingerwheel wasn't permanently attached on the earlier 7 type dials.
There was a fix for this by using some type of lockwasher and later the holder was staked onto the center part.  I read this in one of the station dial maintenance manuals.  You can prevent this from happening by holding the holder and putting the hex nut back on while you are working on the dial.  This unwinding happened to me, but I don't remember how many turns to make the dial return correctly. I don't think you have to disassemble the whole dial to fix this.

[Babybearjs]

I've had to fix those before, they are a pain to service. you have to have the tension just right!

[kka2446]

Hello RotarDad,

Thank you for your help to reset the dial return spring on my WE 7A. I followed your instructions exactly and it all went together very nicely...My dial has the 4 notches on the spring flange.

The two spring ends with the little upturns weren't broken The round 'white metal' circular dial stop just below the spider washer popped loose and everything went flying.

I do have one problem, the dial won't break dial tone, no numbers on my tester. The contacts appear to be making and breaking and the shunt contact, I think that what it's called is made while dialing. I tried a known good dial in the the phone and it worked.  The phone has a 425A network with a 311A EQ, but my test WE 7D dial worked.

Any thoughts would be appreciated, but once again your repair method was spot on...Thank you !

John

[RotarDad]

John - Great to hear the repair worked!  Usually the issues with the dial relate to the position of the contacts upon reassembly.  The contacts should look like this pic.  The dial pulse cam (clear plastic or nylon) should be in about the 10 o'clock position similar to this pic.  The pulse contacts must be closed with the dial at rest.  The other contact set should be open at rest with the black post on the large center gear holding them open until the finger wheel is moved.