WE 550C PBX - Dial Info

[BigBird0000]

Hi Guys,

I am trying to add a dial to a WE 550C PBX.

In the past, I have been told the dial mount bracket was not original...
There are 5 pads on the dial mount: (From Top (back of PBX) to Bottom (front of pbx))

R - Connected to what looks like a red & black wire
GN - connected to what could be a green wire
B - connected to a light colored wire
Y = N/C
W - connected to a light colored wire

Going off the T drawing, it looks like the W does not get connected anywhere (I have redrawn the T, I do not think I made mistakes). It looks like only 4 wires are really used (R, Gn, B, Y)

How can I really tell what wires get connected to what parts of the dial? I have no idea where the wires go... I tried tone trace, but the cable has so many wires, nothing gets through).

Thanks so much, and Happy Turkey Day!

[RB]

Hey Big Bird.
I don't know squat about your dial. insert disclaimer here.
But it looks similar to some I have seen.
From the looks of it, the top two contacts, Y and B, look like the Pulse contacts. the last part of the line out to the next stage, prob a switch.
The bottom is the part for the receiver. the middle contact, and the bottom, allow the signal to flow when NOT dialing.
The middle and TOP contacts, probably short the receiver during the pulses.
I cannot say much more, as I cannot see beyond your pic.
Perhaps, a pic or two of the DIAL and OP circuits would be helpful.
Someone smarter than me will prob chime in soon though.

[BigBird0000]

The dial I have is a BH6, in a switchboard type housing, but without the contacts to connect the dial to the mounting bracket. The dial has 5 screws for connections

I am just looking for which wires would be used for the pulsing, and the "dial in operation" switches.

Only 4 wires are connected to the mounting bracket on the PBX.

(Previously Alex B said the PBX might have been modified for this dial, but I have no idea of where to look)

[RB]

on the second pic, the top, grn and yel wires are the pulse contacts.
On the other three, you will need to determine,"by lookin at the schematics",
Which two you need, the normally closed, or normally open pair.
You could try it both ways, I doubt you would hurt anything...

[BigBird0000]

Yeah, I guess I am going to try the different combinations. At least there are only 4 wires to try

[RB]

Try Yellow and blue to A and B on fig F, is it???

[RB]

Red and green to C and D of fig A, not f, sorry.
do you have the schematic for that pbx?

[HarrySmith]

I have a bunch of 555 board documents on Google. You should be able to view them and I am sure there is a diagram in there>
https://drive.google.com/drive/folders/0B6eDAxemj1VHZjk2NTgwNWItMGUzNy00YzhhLWI4NGQtNzc3MTU4OGE5MjRh