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51-AL ST restoration questions

Started by Sargeguy, December 01, 2013, 05:37:15 PM

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Sargeguy

I am trying to rewire my two 51ALs.  Both have wiring harnesses but they did not come with cords or dials when I purchased them.  I've re-wired a few 151-ALs but this is the first time I've tried to get a 51-AL to work.  The 3-cond wiring harness is intact, I have a 3-cond subset cord and 2-cond handset cord.  Am I missing a separate black cord that connects the switch to BK on the 2AB/2AE dials?
Greg Sargeant
Providence, RI
TCI /ATCA #4409

unbeldi

#1
Here is the wiring diagram from AT&T Specification 4566.
Page 38.  51-AL for individual lines

I believe this connects the transmitter lead directly to the dial terminal.


poplar1

50-AL: 4-conductor harness
51-AL: 3-conductor harness
151-AL: 5-conductor harness

Additional short jumper from transmitter to rack (switch contacts)
"C'est pas une restauration, c'est une rénovation."--François Martin.

Sargeguy

#3
Ahhh!!! SO blue-blue has faded to white and black has faded to grayish blue and white is not actually part of the wiring harness but connects directly from the receiver cord!  I love old cords! Where did I put my Sharpies?
Greg Sargeant
Providence, RI
TCI /ATCA #4409

unbeldi

The 1935 catalog lists the following cordage for the 51-AL:

receiver: R2A (2 1/2 ft. long)
transmitter: T1A (9 7/8 in long)
deskstand: D3A (5 1/2 ft long) and D3B (9 in. long)

Sargeguy

Yes, that's the one:
Greg Sargeant
Providence, RI
TCI /ATCA #4409

Sargeguy

Correction-D3B faded wire equivalents:
Grayish blue=blue
Grayish white=black
Pinkish orange=red
Greg Sargeant
Providence, RI
TCI /ATCA #4409

unbeldi

Quote from: Sargeguy on December 02, 2013, 05:00:51 PM
Correction-D3B faded wire equivalents:
Grayish blue=blue
Grayish white=black
Pinkish orange=red
With the tracers being such thin threads, it can indeed be difficult to ascertain the original color, but the second item (black) is still surprising.

The blue lead in the D3B cord is double-blue, meaning two tracers of blue. Red and black are single tracers.

poplar1

Forget the changing colors--by process of elimination you know the longest one bypasses the switch hook contacts and goes all the way to the transmitter. And on the other end, the very short one will only reach the R terminal on the terminal block. So that leaves BB to BB.

In case you're worried about having the whole thing upside down, just look at the 5-conductor cord inside one of your 151ALs. Almost every 151AL has a D3B cord (originally from a 51-AL) with two additional leads wrapped around it.
"C'est pas une restauration, c'est une rénovation."--François Martin.

Sargeguy

QuoteForget the changing colors--by process of elimination you know the longest one bypasses the switch hook contacts and goes all the way to the transmitter. And on the other end, the very short one will only reach the R terminal on the terminal block. So that leaves BB to BB.

That is pretty much what I did, using "wire" memory and the like. 
Greg Sargeant
Providence, RI
TCI /ATCA #4409