212 KTU #35A, B, and C terminals

[Babybearjs]

just a quick question, I have the 212KTU and the R relay on my 3rd channel is not siezing when called. could I add a .47UF cap to it to help the relay actuate? it works fine when called from within the system, but won't work when called  through the CO... (incoming calls.)

[Key2871]

Is it getting enough power to cause it to seize from the CO. Sounds like it's not. Are you going through an ATA or another piece of equipment to get a ring voltage.
Is it a voip system or a genuine CO type exchange your getting the swing voltage from.
It can't hurt using a cap, because all that's doing is filtering out the DC voltage and just allowing the ring current to come through.

[Babybearjs]

OK, so it won't hurt to add one. it works when the number is called from the other numbers assigned to the system but if someone outside calls, it won't sieze... weird...  I'll add a cap and see how it works...

[Key2871]

Well I suspect it's a voltage issue, if it's not catching with the voltage provided by what ever system is supplying the voltage, it's not strong enough to seize the relay.
So, is this a voip type deal? Or is the supply over copper? It would at least give me a better idea what's going on.
Is there a way to provide another relay that will turn on that will in turn provide the ring current from your own system to seize the ring up relay. That's another solution

[Babybearjs]

this is all a landline service... its weird, I took the jumper off and added a .47uf cap in place and it didn't do anything, the relay wouldn't actuate. so, I put the jumper back in place and called the number, it works when called from the other number, 1 digit off... (line 1 Bank A is 2097 and Line 3 Bank C is 2096.... ) definitely a voltage issue and I'm wondering how to fix it... I have had to put all my ringers on a low bias setting in order for them to work right... so CenturyLink is where the problem lies... at least that's what I'm coming to.... I'll have to talk to a local tech and see what they say...

[Key2871]

So another number from the same source works, but not from the other number on the same.
That's very odd. Have you talked to the provider and say I have a phone that's not ringing with this number is called, and say I've tried other phones and the same problem. Have you tried to measure the voltage, and if your meter has a hold function use it during the ring cycle to see what it reads.
That's the only thing I can think of to get to the bottom of the issue

[Babybearjs]

haven't check the ringing voltage yet... I was asking about the gapping details for this series system... I'm wondering if the relay is too over gapped...  like a spark plug, if its not gapped right it won't fire... that's why I tried to add the cap... hoping it would help, it didn't. maybe it needs a different value? the other thing is these relays are dual coil windings... 1 winding is the line and the other is the control... weird.... oh well, live and learn... I just wish I had a master terminal pinout list telling me what all the terminals do... the schematic covers most of it, but still there are terminal that are unassigned and I'm wondering what they do? I know some of them are commons...but to what, I haven't learned yet. I would love to see what features these units were capable of... I have a 210KTU assigned with this too, so that is connected... what else could be attached to the 212KTU to make it special? the 200 series KTU's are so old that no one knows anything about them hardly anymore... all the techs now know 1A2 and newer.... 1A1 is kind of too old.... (But it works great!) so getting good help is hard...

[Key2871]

As for the coil not sezing on one area, I would simply swap the lines just to test that relay, Then test.
If you have the same issue its probably a bad coil section.
And try using your systems ring voltage, just disconnect your incoming line. And if it works then you have your answer.
As for finding a replacement 212. Beats me where you'll find one.

As for adjusting the springs, grab a feeler gauge and turn off your system, then find another relay nearby and do a gap check.
To adjust, I would source a relay contact adjuster tool. A EM pinball adjuster might be a good start, some of the springs in the system may be slightly larger.
But you may be able to modify the tool some to fit the KSU springs.

As for the terminals schematics, have to looked in the BSPs for key system 1A specific?
I think I looked at one point but I don't recall seeing schematics on terminals, but I'll look again tomorrow.
And TCI library may have something, or call and talk with Phil. He had schematics of the 400 cards in a video I believe it was him. But he has a lot of practices on key systems, and other things too.
As I've said I don't know that mulch about those old systems as I've never really worked on them.
Just the 208 rotary intercom part as I had one years ago that was in my first system.

The guy who removed the system had cut a bunch of wires when he removed it.

I got everything working as far as dialing signalling stations etc. I was amazed I figured it out, but it was also quite easy once you got the just of what every thing did. Because I added a few station that weren't connected and once I got how that unit and the other one worked it all just clicked.

But it didn't just happen, it was a lot of testing tracing etc. Over all I think the KTUs are simple in design and workings, it's just a matter of getting into the head or who designed it.
And I did that my using a continuity tester, a VOM and examining the KTU your working on.
Then I figured out a lot of the concept of the unit.
It's time consuming and at times frustrating, but take breaks write how you trace your findings. And see if you can do a schematic you think is what it is.

That's how I've done a lot when it comes to the old stuff, and a few hick ups along the way, but over all I figured it out.

[Babybearjs]

well, I do have a spare unit if I have to switch it out, the problem is having to completely wire it in... thats why everyone loves the 1A2 and later systems... so much easier to work on.,.. I do have a WE 551C that I'm saving as a spare in the event this system finally gives up the ghost. so far, its doing OK except for this little problem. all the phones are working like they should... no major noise on the line like before when I was using Cat5 and had a spaghetti of a mess under my house. I have the intercom working right and the #208KTU array properly setup... so, all is good... even my ethernet is working right! so I guess I'll just live with this issue for now... I'm just going to have to tinker with it until I get it right... now, what do you know about ATAs and free phone service?

[Key2871]

Ok, John, I'm looking at schematics for 1A circuits, and I wonder if they renumbered KTUs in the 1A1 system but electrically they are at least similar.
Because in BSP 518-112-421 the circuit is for a ring up circuit they labeled 15D. The 15D is a tube type with a varrister in the circuit as well.
If it's electrically the same thing then I wonder if the terminals are also the same. Then there's the 14A, that has a 1uf cap in circuit to a relay coil on terminal 5, terminal 4 shows 1350 ohms between term in 4 and 5.
That look to be the coil resistance and if that cap is bad in yours then I think that would answer what's wrong with yours.

If you have your spare 212 unit get it put it on a table, using your VOM in either ohms mode or continuity and while looking at the BSP see if anything is familiar between the two.

So you may have your schematics basically speaking. The terminals are shown and if they are the same there you go.
Looking at a 212 KTU in the book it shows schematic information, shows terminal numbers I the KTU and what lead from the keys go to which terminal.
This is VOL 2 in the Key Systems Manual.
If you don't have these, go to TCI and look up Key Service Manuals, and pull up section 518-112-421 and it continues from there.

Because under 420 section it shows the schematic for the 57A witch translates to a 208 KTU, rotary dial intercom.
I'm not going to try and get into the details if these are two vastly different KTUs, so do some testing with your spare 212 and meter and see what you come up with.

Now the 212A has some schematic information in
Section 518-114-110 that's fairly detailed with terminals and how it's connected to the Key set.
It states it's for CO/ PBX line Circuit with lamp flashing and incoming signal time out circuit.

With that I've listed and sections that should answer all your questions on what goes where and terminal numbers etc. It does not show the lead color codes in the phone set, but it does tell what the terminal should be connected to in the phone set. As in A H terminals in the Key.
So that should get you where you want to be
Its a vast schematic on one page. So your going to need to know what your wires are coming from in your phone sets, and it talks about 5A, 6A etc terminals it's not clear if those are designations on the unit or not.
I've not worked on these so I don't know.
But it seems to be terminal numbers on the KTU.

EDIT, there is no mention on spring contact gapping.

[Babybearjs]

Thanks. the 1.0uf cap info helps. I'll look at the BSP and study it more, Thanks.

[Key2871]

John, I'm perplexed. It the header of this message you mention 35A, 35B and 35C terminals.. To what are you refurring? Because I see those mentioned in the practice, but there is no terminals with those designations. It mentions those under punching for CKT 1, 2 or 3. But that's when a 101A or B is used, of which I can't find either.
So why did you mention those?

[Babybearjs]

stupid me... I meant terminal 36.... the lead is suppose to go to the 211 KTU, if used... after looking at the schematic, I realized I made that mistake about the title... terminals 31 and 32 are the tip and ring in.... 36 goes through the 211 and back to the tip side of the line. its only section C on the KTU I'm having issues with...