[Panel] Sarah troubleshoots Incoming #30 

I'm a former ESS switchman for N.Y. Telephone. I've seen many retired panel offices, but never a working one. This is very interesting.

Sarah, it is such a joy to see your devotion to this precious Panel switch. You give it life, you resurrect its soul, you are its savior. You are truly an angel, Sarah!

I still remember a trouble with a sequence switch almost 50 years later. A wire clipping embedded in the bear grease was causing a trunk failure in the #1ESS where I worked. Also, we used to have a trouble clearance code "CBM" - cleared by magic. Another was CCWT - came clear while testing.

Sarah: "*incomprehensible-telephony-speak*...just like a car's camshaft..." Me: "Ah...now you're speaking my language!"

Those old machines have soul! Not like the digital crap from the present. These videos bring me back to my highschool( telecommunications specialty highschool) years when I was practicing on the school's 50 lines cross bar switching system. I loved sitting and watching it in action...Love your channel!

Reminds me of my bell system SxS cama system trouble shooting days. Very happy memories. Thank you so much, this was very interesting and gratifying.

I'm in awe at the ingenuity of the engineers that designed this electromechanical marvel. Fault finding was much more satisfying back then, tracing the issue logically down to an individual part. Well done on tracing the fault!

Fault finding is one of the most fun and satisfying things in electronics. Sometimes frustrating, but in the end it feels so good to have found it!

This video was excellent! I suspect that wear from continued working probably rubbed away enough crud from the contact to get it behaving.

Funny - starting at about 14:07 I can hear a shaft squeaking. Evan Doorbell actually mentions this phenomenon in this recording (www.evan-doorbell.com/production/GE9_1.mp3 - at 10:35) and you can hear the squeaking in some of the phone tapes.

Really interesting video, nice to see the details of how the switch works, and is supposed to work, and I really enjoy the real world troubleshooting, and your explanations of things. Please keep the videos coming!

Is that diagram glued to apiece of wood???? That's kinda "olden times" ;)

Fascinating, loved watching this video and appreciate the time taken to record and publish all your videos. I will be in Seattle in early October so maybe I’ll get to see the panel switch in real life, Strowger dominated the UK.

Awesome job on figuring this out. I especially like the "tea cart" that looks cool. Something MA Bell made? Or someone else's idea. Keep up the cool vids, very informative. I like switch gear.

When I was a business analyst we used to use a methodology called SSADM which used states as a key component for designing old fashioned computer batch programs in Pl/1 or COBOL. I was taken back to them by your sequence switches 👍.

This is such amazingly primal electro/mechanical technology, not a single tube, transistor, diode, nor integrated circuit. Great work troubleshooting by the way. Geez, the though of designing, engineering, manufacturing, installing, and documenting these amazing machines makes my head hurt. The scan you linked to is awesome! And navigating those docs and schematics ... wow! Also, first step in the official troubleshooting decision tree: did you mess with it yes/no? If yes, are you an idiot? etc ... and oh yeah, when all else fails, look at the diagram (RTFM in my troubleshooting vocabulary).

I enjoy troubleshooting and especially when doing it with someone of similar mindset. You would be fun to work with. Your thought process is very much like my own. I found myself talking to the screen during this video! I hope you do more troubleshooting videos.

At 38:05 love that tone bar. Haven't heard that in a looooong time.

Great video! Thank you for putting it together. Really enjoyed learning more about the system and the "ghosts". Looking forward to more. :D

The more I see of telephone switching gear, the more I realize just how intelligent the people were who designed this stuff.

I have only just found your channel. This was my first video and I found it fascinating. I have my own PAXes and know how satisfying it is to sort out a problem. I find the concept of the panel system difficult to follow but with your help I am getting here. Thanks 😉

I've liked, done some basic playing with phones back in the 70s. I have only have a very basic of idea how these switch machines work, but found this fascinating to watch you troubleshoot the old way. I suppose I never considered the effort that went in to designing them on paper before assembling them, right on through to maintaining them.

Very interesting. I think your sanding you did likely got rid of the ghost. One thing you need is lots of patience for this stuff. I used to take violin lessons in the early 1970s and still have the violin and rosin even though I don’t play anymore. Thanks for the video. Please make some more. 😀

@ConnectionsMuseum Maybe some day you could do a video focused on the tea wagons? What's in them, their capabilities, how they actually connect to a switch, what's different from this one to the one with the meters that you recently "re-tired" etc...

This was a great video. Good troubleshooting, it can be pretty satisfying when working on this kind of equipment and really having to trace out and understand the system to find the problem, even when it involves working out the "ghosts"

Maybe it wasn't so much as a "ghost in the machine"> It may have required a few cycles for the sanded brush to seat/burnish against the cam, or for the residual filings to clear away.

Good troubleshooting! Thanks for sharing this with us Sarah :-)

When i worked on ibm computers they said you never say bend it. You just made an adjustment Good job

You folks are fantastic ! I love what you’re doing !

What a racket in the room... servicing this equipment must have been an arduous task.

9971 mean anything to you. Or maybe 958 ??

Does the sequencer for the selector frame reference translators? I don't have a block diagram of a panel switch. I should probably go try to answer my own question 😊 awesome video BTW. Please keep them coming!

Did you manage to get a wire pair strung from the museum to your home?

Brings be back to my roots!

Do you work in the 1900's?

Hey, some good and (eventually) productive confusion there. I recognise some of the expressions, coming as I do from a day of debugging software... More videos like this are good (but hopefully with less ouch).

Very impressive, I love to see a tech st work, the problem the process, the final repair, just doesn't get any better. Thank You, I always like these videos..

Why are your schematics and or wiring diagrams on pieces of wood!?

Wonderful video Sarah! It was great seeing you go through the whole process I was wondering, on that schematic you looked at, some of the numbers had fractions... why is that? multiple contacts?

👍 the the “thumbs up Sarah” photo stuck on the equipment frame in the background.

It's just your magic touch Sarah. Should setup a webcam in your house pointed at your house phone for testing purposes!

6:15 Even with the diagram linked in the video description it took me a bit to understand how to read this.... it's really unintuitive that the A cam's outer contact is labeled with its _open_ states while the contacts of all other cams are labeled with their _closed_ states.

"Ouch, many volts"

super film

Hey Sarah, what's up with the strange spacing of the button panel on the Tea cart? 5:00 for example. Some of them seem to be much closer to each other. Is one bank out of alignment or was it designed that way?

@2000 a narrative of the switchings

A comment and a question. The comment is that as amazingly wonderful as this stuff is, what's really mind-blowing is how failure resistant it is. You've got a state machine that's doing the wrong thing, and while obviously calls that get routed through that don't get processed correctly, the rest of the switch just keeps on chunking along. If I had corrupted memory in a modern digital computer, eventually, I'd end up with the whole machine crashing as pointers got trashed and the damage just kept spreading. The question has to do with the nomenclature. It get that "1/8" means "positions 1 through 8". So, why at 7:13, just to the right of your finger, does it say "1-2-3-4-5-6-7-8-9" instead of just "1/9"? And even more confusing, a little above that, what's "11/11-1/4" Does that mean a quarter of the way past position 11?