Making a WE551A Functional - Work In Progress

[ramegoom]

Starting to make more sense. I'll re-arrange the spreadsheet. Baby steps here.

[ramegoom]

Starting to make sense?

[Alex G. Bell]

Starting to make more sense. I'll re-arrange the spreadsheet. Baby steps here.

Good!

Do you have at least a 24VDC (or 18-30V) supply available?  A good cheap source often found in thrift shops is Hewlett-Packard ink jet printer power supplies with dual 16V & 32V outputs.  These are switched mode power supplies so they have no audible ripple at power line frequencies or multiples. 

The typical 24VDC "wall wart" sometimes found usually are simple line frequency transformer-rectifiers with a single stage capacitor filter.  These will have an intolerable amount of ripple unless supplemented with a series low resistance inductor and second capacitor to form a pi-section filter. 

In the long run you want a proper key system power supply which includes ringing current: 20 or 30 Hz at 75-90VAC.  A Tellabs 8050 (if you can find one at a reasonable price) is an excellent choice because it is compact, uses switched mode for minimal standby power drain, and is switchable for either 24 or 48VDC and 20 or 30 Hz.  Ideally you want 24V & 20Hz.

[Alex G. Bell]

Starting to make sense?

Yes, that's correct. 

You might as well add a second set of columns for the OR-WH binder since the power connections are probably among those leads after the first 5 pairs assigned to STA Ls 26-30 on BL-WH through SL-WH.

The 10 CO trunks are probably on BL-RD through SL-BK of the OR-WH binder and power leads down among the YL and VI groups if they are in the same cable at all.

[ramegoom]

My playground involves electronics, so I have lots of lab equipment, meters, power supplies and such. I am thinking a 24v. switching power supply might work. Maybe 5 amps? I work in the automotive wiring industry, and my company manufacturers engine wiring harnesses, so I have access to thousands of different connectors, terminals, miles of automotive wire, etc.

Next, I see that I need to find a power supply that will generate the ring voltage and dial tone. I assume this will hook directly to the cable? Also, hoping that all of the panel lamps have a direct connection to the cable. Each row of lamps has a common bus tying all of them together on one wire. Making more sense now.

And THANKS for the help.

[Alex G. Bell]

My playground involves electronics, so I have lots of lab equipment, meters, power supplies and such. I am thinking a 24v. switching power supply might work. Maybe 5 amps?

I remember you said some of this.  That's why I suggested a bench supply for starters. 

(As I stated earlier): 500mA to 1A is sufficient.  Lamps pull ~30mA.  An off-hook phone can draw 100mA while talking but usually less.  With 10 cord circuits the max. number of off hook phones possible would be 20 and that probably will never happen in your use.

I work in the automotive wiring industry, and my company manufacturers engine wiring harnesses, so I have access to thousands of different connectors, terminals, miles of automotive wire, etc.

I don't see much need for that stuff at this point.  As stated earlier, industry standard 66 blocks or 25 pair Amphenol connectors would be appropriate for terminating the raw end of the 50 pair beige cable.

Next, I see that I need to find a power supply that will generate the ring voltage and dial tone.

As stated earlier, a Tellabs 8050 would be a good choice.  There is no use for dial tone in a manual switchboard.

I assume this will hook directly to the cable?

As stated earlier, cable leads MAY HAVE BEEN assigned for the power inputs but until I study your photo of the face of the block and compare with what's shown in the SD for power terminal connection points we don't know yet.  If leads have not already been assigned, the 10 available spare pairs should be sufficient to assign pairs for this purpose.  However some prefer to put the power unit inside.  Some object to having an AC cord running into it.  Where you locate it and what you do with the loose end of the 50 pair cable will probably determine which is best.

Also, hoping that all of the panel lamps have a direct connection to the cable. Each row of lamps has a common bus tying all of them together on one wire. Making more sense now.

As said multiple times previously: the station line lamps on the face of the swbd will light when the corresponding T&R pair on the cable is closed with a DC path of <100 ohms.  The supervisory lamps on the keyshelf are controlled by relays on the gate.  Re-read the history for more details.

And THANKS for the help.

You're welcome. 

You're frequently asking questions which have already been answered one or more times.  It would be best for you to read through the entire topic from start to finish since your becoming familiar with this technology is somewhat of a layered process, therefore things you may not have understood previously may be understood and assimilated on re-reading, avoiding the need to ask questions which have already been answered.

[ramegoom]

Sinking in on my end. Sorry for the repeat questions, just unclear on my end.
Here is what I want to "populate" with descriptions in the blank spaces. This will help me set up the cables. I think I have it covered so far.

Is there any particular document that describes the pairs and what they control?

[Alex G. Bell]

Sinking in on my end. Sorry for the repeat questions, just unclear on my end.
Here is what I want to "populate" with descriptions in the blank spaces. This will help me set up the cables. I think I have it covered so far.

Is there any particular document that describes the pairs and what they control?

Getting closer. 

An error I did not notice before is that pairs 11-15 are paired with BLACK which is abbreviated BK.  Both BLue and BLack cannot be abbreviated the same as BL.

Another error is that pairs 16-20 are paired with YL, not GN.  There are two non-overlapping groups of 5 colors, listed in Reply #30.

The two binders of the cable do not correspond to the two terminal blocks because the binders each contain 25 pairs and the terminal blocks are 4x20 so they have 40 pairs.

The switchboard is equipped with 30 stations so, as stated first in Reply #25 and again in Reply #30, the first 5 pairs of the OR-WH binder (BL-WH thru SL-WH pairs) are the last 5 stations: 26-30. 

The next 10 pairs (BL-RD – SL-BK) are the 10 CO trunks. 

The MISC terminals (as stated in Reply #25) IF THEY ARE CONNECTED TO THE REMAINING PAIRS, would be on the YL and VI groups of 10 pairs in the OR-WH binder.

I've already explained what the STA L and TRK pairs do.  The cable pair colors they are assigned to are job-dependent and have already been explained.  The only thing which has not been covered is the power input terminals which I need to look up.  It does not seem like you are ready for that anyway.

[ramegoom]

Finally sinking in 
Here is the map and I verified it with the STA L block. All the colors are identified, and there are 30 pairs. The rest of the terminals have no wire on the output end but there are wires populated on the input. I am pretty sure those wires go into a cardboard tube full of un-terminated wire, that would be installed if there were more jacks and lamps on the top row, which is blocked off. Once I identify each function, I'll move on to the MISC block. Seems there are jumpers soldered across the terminals in some spots. I'll identify those along with the colors.

Your details are making sense to me now.....

[Alex G. Bell]

Finally sinking in 
Here is the map and I verified it with the STA L block. All the colors are identified, and there are 30 pairs. The rest of the terminals have no wire on the output end but there are wires populated on the input. I am pretty sure those wires go into a cardboard tube full of un-terminated wire, that would be installed if there were more jacks and lamps on the top row, which is blocked off.

That's correct.  You need to add a line to your table above 1 and between 25 and 26 showing the binder colors.

Once I identify each function, I'll move on to the MISC block. Seems there are jumpers soldered across the terminals in some spots. I'll identify those along with the colors.

Your details are making sense to me now.....

I don't know what you are referring to with the statement "once I identify each function".  I've already identified the 30 STA L + 10 TRK pairs. 

Yes, I'd expect to see jumpers in the MISC part of the block.  Once I look up the terminal assignments for the MISC leads they will probably make sense.

[ramegoom]

Being new, I am looking to find out what each wire does. I have no idea how this system actually works, but want to learn as much as I can, i.e. where each terminal connects internally. Do they connect to a relay coil, lamp, switch, jack, etc.

I also mapped the TRK and MISC wiring. I assume the TRK wires to each of the outside line jacks on the bottom of the panel. Looks like line 10 has no connection.

I'm going to also assume the MISC wiring that is jumpered and joined would accommodate a high power connection? Seems to make sense since they're tied together.
Hopefully a quick learner from here. It is starting to make sense.

[Alex G. Bell]

First, your chart:
1st: Pair colors are normally expressed as R/T, so BL-BK, not BK-BL.

2nd: you inconsistently flip back and forth.  Pr/s 4 and 8 are flipped relative to the rest (which are all actually flipped).

3rd: Pr. 3 is an invalid combination of two R colors, should be BK-GN (using your existing T/R order).

4th: Pr. 4 is actually Pr. 3.  Pr. 4 should be BK-BR.

Green is normally abbreviated as GN, not GR, perhaps to avoid confusion with GRAY, which is called "SLATE" for the same reason.

What you ask is far beyond what can be recapped here.  This general tutorial on cord PBX switchboards may help you understand in general terms:
BSP 534-400-110 - Fundamental Circuit and Operating Features - Common Manual PBX Switchboards

but Google does not seem to find it.  Maybe you will have more success than I did.  Don't fall for citations of it which appear in 534-000-000 indexes.

You will need to study and understand the specific SD for the 551 to understand how the 551 specifically works and how components are interconnected.  There are 005-division BSPs which explain the symbology used on SDs and other drawing types.  Look in the TCI library whose URL I stated earlier.

MISC terminals are not necessarily strapped together to increase current capacity of leads.  There are other reasons.  There is no high power involved.  As I said, the whole thing operates at < 24W.

Being new, I am looking to find out what each wire does. I have no idea how this system actually works, but want to learn as much as I can, i.e. where each terminal connects internally. Do they connect to a relay coil, lamp, switch, jack, etc.

I also mapped the TRK and MISC wiring. I assume the TRK wires to each of the outside line jacks on the bottom of the panel. Looks like line 10 has no connection.

I'm going to also assume the MISC wiring that is jumpered and joined would accommodate a high power connection? Seems to make sense since they're tied together.
Hopefully a quick learner from here. It is starting to make sense.

[ramegoom]

Thanks for your input. Obviously I need scrutiny.

I will fine-tune and correct the charts. These are sort of preliminary as I was poking around the terminal blocks and taking notes. I am going to get some close-up pictures to verify the T-R colors that align with the terminal pin number. It's kind of odd, the first block in pairs, the second block in terminal numbers. It'll make sense eventually.

I just need a useable wiring diagram so I can determine what each colored wire does with respect to the outside world. So, to hook up a phone extension, which two wires do I use, etc.

I'm pretty sure the schematic that comes with the unit is somewhat understandable now that I have at least an idea about the connections on the terminals.

I realize I have to go thru a complete learning curve before I can start adding power, phones, bells, etc. Still is a mystery to me, but I'm all about learning. Still need to understand about all those multi-contact relays as well...seems there's an awful lot of them for what I am trying to accomplish, so most likely they'll just sit there and do nothing. Still, need to read, read, read. I'll get there.

[Alex G. Bell]

It's kind of odd, the first block in pairs, the second block in terminal numbers. It'll make sense eventually.

Not so.  The TRK part of the TRK & MISC block is in pairs too.  Any voice circuit is likely to be in pairs.  Power and misc. leads not.

I just need a useable wiring diagram so I can determine what each colored wire does with respect to the outside world. So, to hook up a phone extension, which two wires do I use, etc.

Been over this many many many times by now.  Telephones connect to the STA L pairs.  CO trunks connect to the TRKS pairs.   The first phone connects to STA L pair 1 & will appear on the 1st jack which is marked "1".  The last 30, 30 and 30.  Pretty simple!  Nothing convoluted about it!

I'm pretty sure the schematic that comes with the unit is somewhat understandable now that I have at least an idea about the connections on the terminals.

It's a wiring diagram.  It shows the colors of wires and the terminals they are connected to.  It's useless for understanding how it works.

[TelePlay]

I realize I have to go thru a complete learning curve before I can start adding power, phones, bells, etc.

You need at least two telephone sets, or as many as you want up to 30 max, to "use" the board, to show how it works, but I got lost in the detail of whether or not you have a land line and want to hook the board up to that line using the CO TRK terminals.

Do you have a land line or VOIP type line and if so, do you want to attach the board to it?