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66Block used for 555PBX

Started by USWCboy, April 05, 2023, 10:56:53 PM

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USWCboy

Greetings Classic Rotary Phones forum members!
I have been a long-time reader of this forum, fact is, I have used plenty of the technical discussion for restoration of my own collection which does include my technical issue of today. Sometime back I acquired a 555PBX Switchboard. I was lucky with this one in that it was owned and operated by the Mountain States Telephone and Telegraph Company, used inside their training center that was at one time down in Colorado Springs. The board itself was given to a retiring instructor, who then sold it to another former employee from US West, and wound up with me, who at the time was working at Qwest. Needless to say, the former owner was happy in that it was staying in the "family" so to say. Since acquiring I was able to wire it up and get it to work with local extensions off the board. At the time of procurement, I always wondered if the 25pair cable attachments would still be hooked up to provide a bit of portability. Recently, I decided my wire wrap on the back binding posts was no longer sufficient, and decided to start investigating the 25pair cable(s) and amphenol connectors. Purchasing a telco type split 66block I began wiring it out. Now, having very little copper experience in the telecom industry (fiber/backbone networks is my specialty) trial and error rued the day trying to get things back into a working condition. After blowing my fuses once, once being enough as they are hard to find, I dug into the fundamentals section of the BSP and learned I was doing it all wrong, my count on the 66block was incorrect, and my assumptions on where the actual connectors were on the amphenol was wrong. I believe I am now on the correct track with the positions (amphenol vs. 66 block appearance) I still cannot get power back to the board. The good news, the current configuration is no longer popping my talk and signal fuses, yet the issue still exists = no power to the board. I have read and re-read and read it again the BSP's on the 555PBX along with the connector's addendum put out by Pacific Telephone. Yet I still can't get the power correct. I am hopeful that with the pictures you will see below, that we can come up with what I am missing here.
**BSP - SECTION 536-550-210PT

HarrySmith

Welcome to the forum.  I can't help you with your wiring but we do have a lot of info on your board in our switching section. Good luck
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

poplar1

I don't think the 22-24 guage wire you are using for power is the recommended size. Why not connect the power directly from the power supply to the PBX, using larger wire or doubled up small wire?
"C'est pas une restauration, c'est une rénovation."--François Martin.

USWCboy

Quote from: poplar1 on April 06, 2023, 09:51:16 AMI don't think the 22-24 guage wire you are using for power is the recommended size. Why not connect the power directly from the power supply to the PBX, using larger wire or doubled up small wire?
Thank you for the note. Wire in use is rated to 300v, so I don't think the wire is preventing this from coming back on. As explained in my opening post, this was working prior to using the 66block. I was hoping to use the 66block to increase portability of the board, but it looks
Like I may be going back to a direct connect as it was working prior with no issues. And that was using the same wire as in place now.

poplar1

Can you photograph the connections of your 25-pair cable inside the PBX?

If you are using Table B from BSP Section 536-550-21PT Appendix 1 in the TCI Library, it is showing using whole pairs for Battery (Pins 19,44; 20,45; 21,46) and Ground (22,47; 23,48; 24,49) with the Ringing generator connected to 25 and ground to 50. Wired this way, you would have Yellow-Brown, Brown-Yellow, Yellow-Slate, Slate-Yellow, Yiolet-Blue, and Blue-Violet all going to the BATT terminal in the PBX.   Violet-Orange, Orange-Violet; Violet-Green, Green-Violet; Violet-Brown, and Brown-Violet all connected to GROUND terminal in the PBX. 24VDC filtered (A battery) from the power supply connected to 19,44,20,45,21,46  and Ground to 22,47,23,48,24,49 on the left side of 66 block (not split pairs as you have now).
"C'est pas une restauration, c'est une rénovation."--François Martin.

Hill Haven Telephone Company

SxS phil made a decent video on how to do it


USWCboy

#6
Quote from: poplar1 on April 09, 2023, 11:05:43 AMCan you photograph the connections of your 25-pair cable inside the PBX?
I sure can, they are attached here. Further my apologies for my late response back... the month has gotten away from me.

Just to make sure I understand a split pair (Using the TIA568B Ethernet standard (1/2)W/OR-OR, (3)W/GR, (4/5)BL-W/BL, (6)GR, (7/8)W/BR-BR for reference) (1/2)W/OR-OR, (3)W-GR, (5)W-BL, (4)BL, (6)GR, (7/8)W-BR/BR. The split pair would be at 5 & 4?   

USWCboy

@poplar1 " whole pairs for Battery (Pins 19,44; 20,45; 21,46) and Ground (22,47; 23,48; 24,49) with the Ringing generator connected to 25 and ground to 50."

Split pairs are gone now!!

I have rewired the 66block as you suggested above...the ring circuit is now working! However, I am not getting lights when and extension goes off hook, no lights when an extension is on hook with a cord in that extension. Talk circuit is also non functioning. Seems like I am missing something in the back, either strapping or perhaps I've missed a pin on the 66 block? Dang nice to hear it ring again, but still have more to do. I'll keep looking at the diagrams, but I surely would appreciate additional guidance.

poplar1

Quote from: USWCboy on April 05, 2023, 10:56:53 PMSince acquiring I was able to wire it up and get it to work with local extensions off the board. At the time of procurement, I always wondered if the 25pair cable attachments would still be hooked up to provide a bit of portability.


If it was working before, I would first check the A battery (24 Volts DC filtered) fuse on the power supply. Then temporarily disconnect the connections at the power supply for A battery and its ground, and run a new wire from power supply directly to the block on the PBX for 24V battery. (Ringing generator connections seem to be OK.)
"C'est pas une restauration, c'est une rénovation."--François Martin.