W.E. 151AL transmitter

[neondave]

Good morning,

            A few years ago I purchased this 151AL.  It has an F1 ( ? ) transmitter installed ,but also came with the orig.  transmitter parts in a baggie. I was thinking of trying it out.

           Can this be tested in some way before I install in the phone?    Or should I leave the phone as is ?

  Dave

[dencins]

You would need to mount it on a face plate to test it.
A couple of items you would need:
1.  An insulator between the face plate and the diaphragm.  This can be made from vellum (paper)
2.  An mica disc (insulator) between the carbon module probe and the diaphragm.
As long as the mica seal has kept the carbon granules in the carbon module, it will probably work.

Dennis Hallworth

Update - if you want to make the insulator between the face plate and diaphragm draw two concentric circles on a piece of paper.  Outer circle is 2 1/2" and inner circle is 1 3/4".  Cut out the two circles and the ring that is left is the insulator.

You can test it without the mica disc but if it is to be used I would recommend one.   

[neondave]

Hi,
       Face plate insulator is good ?

        Not sure what I need for the probe/diaphragm  ? insulator

         I can see the granules  in the module

         Is there a diagram or photo of  the correct Assembly of all needed parts ?

         Thanks,Dave

[neondave]

Hi,
       Face plate insulator is good ?

        Not sure what I need for the probe/diaphragm  ? insulator

         I can see the granules  in the module

         Is there a diagram or photo of  the correct Assembly of all needed parts ?

         Thanks  ,Dave

[unbeldi]

         Is there a diagram or photo of  the correct Assembly of all needed parts ?

         Thanks  ,Dave

Please see if the attached diagram helps. This is from the 1929 catalog. The quality isn't very good, but perhaps good enough.

[neondave]

Thanks !, looks like I just need the   insulator between probe and diaphragm ? ,  can I substitute mica with something else ?

   I may have a mica scrap around the house

[TelePlay]

I may have a mica scrap around the house

If you don't you can search eBay for "sheet mica." I got some from Europe some time ago that worked well. Seems the good sheet mica comes from eastern Europe. It's a little tricky cutting and drilling the thin plates but the learning curve is quite steep. Here is a link to one such source,

http://www.ebay.com/itm/ex-USSR-Mica-Sheets-Size-60x50x0-05mm-QTY-48-/251271902917

. . . many other sources can be found on eBay for you to choose from. I found using eBay far superior to looking at rock shops and other places that "may" carry the stuff locally. The cost of shipping was much less than gas expended in fruitless searches locally.

[neondave]

I just need a small 'button'  to set down in that area  ?  How critical is thickness ?   I may have some scraps from transformers or bits from my neon days

[dencins]

As long a the insulator between the diaphragm and face plate isolates (no continuity between the two) then the mica disc becomes extra insurance as an insulator.  If there is continuity between the face plate and diaphragm then the mica disc would be needed or the diaphragm to face plate insulator would need to be adjusted.

I have been told the thickness of the mica disc may influence transmission but I have no evidence how thickness influences it or how much. 

My opinion is WECo used the mica disc in case the other insulator was not properly aligned during mfg or field repair.

Dennis Hallworth

[dencins]

The mica I have been using is 0.004" thick purchased from McMaster Carr.  I bought 2 -  3"x5" sheets in 2007 that I am still using.

I cut it with a hobby knife using a 5/16" steel flat washer as a pattern.  I cut around the both around the inside and outside of the washer.  The inner disc becomes the carbon module to diaphragm insulator disc.  I use the ring as a replacement seal if I rebuild the carbon module.

Dennis Hallworth

[TelePlay]

That's very good information, Dennis. I was working on a non-WE transmitter and just copied what was there to fix a problem.

And, seems McMaster Carr sells everything, almost. A good source for a lot of stuff.



xzzx-micadiaphragm-xzzx

[dencins]

Here is a picture of the 5/16" steel washer, mica disc and carbon module seal.

[neondave]

Good morning,

   Well , I wired up the orig. type transmitter and left my wife a message on her cell and it was loud & clear !  As good or better than the F1.  The F1 was packed in with foam, so maybe that affected the performance.

    Now, does it matter which of  the two wires are connected  to one terminal or the other ? It works, so maybe not,

     I did find a scrap of mica that was .004-.005 thick and just large enough for that area on the diaphragm.

      Thank you to all  for your info !    Dave

         

[Kenton K]

Yes, you are correct. It does not matter; Just which ever one fits the best in the transmitter cup.

Ken

[rdelius]

I cheat and use a paper hole punch and a scrap of plastic