Author Topic: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set  (Read 967 times)

Offline Ktownphoneco

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Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« on: November 14, 2016, 04:12:19 PM »
Good Afternoon All  ....   I'm looking for a schematic diagram for a Western Electric 2504-BM desk set.    I've done a search of the TCI Library, and found some listings for components, like dials used, etc., etc., but not a schematic.       
If anyone has one in either "PDF" or as an "image" file, could you post it for me please.

Thanks very much !

Jeff Lamb

Victor Laszlo

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #1 on: November 14, 2016, 08:07:28 PM »
529-225-102 is the BSP you need. I believe you'll find it in one of the Station Specialties handbooks, or the Data Service handbooks. Since it's basically a 2500 set, with a few extra features, such as the extra SWHK / exclusion key contacts, you should be able to take a BSP for a 2500 and annotate it with the extra stuff by tracing the wires and the components inside the set.

Offline Ktownphoneco

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #2 on: November 14, 2016, 10:29:35 PM »
I opened the set fir the first time yesterday, and started getting into the connections today.     I've found a number of conductors from the switch hook taped and stored, which makes me wonder if there are any components missing or functions that have been made inoperable as a result.     A schematic would make it very simple to see if in fact that's the case or not.    I have a 1980 station service manual, but it doesn't include the 2504, or 529-225-102.  I don't have a station specialties handbook or a data service handbook.     I searched the TCI library for BSP 529-225-102 and nothing was found.    Most everything in the library now has been subjected to the optical character recognition process, so even if that BSP number was included in a lengthy document, it should have come up in the search results.   
The set has had a "840364202" polarity guard module installed.    That and the insulated and stored conductors would indicate that the set has been somewhat modified at some point, but without a reference point as to what should be in the set when it left the factory, I'm kind of poking around in the dark. 
But I have the set functioning correctly as a regular desk set, so I'll leave things as they are until I find some documentation on this model.     According to date stamps on the base of the set, and it's components, the set's manufacturing date seems to straddle Dec. 1982 and Jan. 1983. 

Jeff
« Last Edit: November 15, 2016, 09:19:36 AM by Ktownphoneco »

unbeldi

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #3 on: November 14, 2016, 11:06:21 PM »
I think the 2504 was capable of four-wire services, so you would expect some leads to be stored when in 2-wire mode, and probably some more for special arrangements.

I didn't find a diagram either yet, but will keep looking.  I doubt the BSP would be in the standard handbooks, this was for a special service that was not commonly installed.
« Last Edit: November 14, 2016, 11:08:23 PM by unbeldi »

Offline paul-f

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #4 on: November 14, 2016, 11:15:45 PM »
BSP division 529 is for sets that are intended solely for use with specially engineered lines -- not for general telephone use. The BSPs in that division are generally difficult to find. I don't believe one has been contributed to the TCI Library yet.

You might try the diagram for a rotary set with similar features - 500ABMW.

Does your set match the components listed here?
   http://www.paul-f.com/we2500typ.html#2504

Many of the 2504s available on ebay over the last few years were surplus sets modified by the Telephone Pioneers in Virginia to be effectively 2500DM sets. They didn't change the set markings, so buyers getting one based on the bottom marking may be disappointed. It wouldn't be surprising to find that yours was modified over the years for use as a standard desk set, as others undoubtedly re-purposed them as well.
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Offline Ktownphoneco

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #5 on: November 15, 2016, 10:02:51 AM »
Thanks Paul and Karl for that very accurate information.   Paul, I read that page from your web site, and compared it with what's in the set, and your explanation regarding the surplus 2504 sets that were modified by the Telephone Pioneers, appears to fully explain and match the changes made to this particular set.    The T/T dial pad in this set is 35C3A, while the dial pad which was originally installed, was 35C3B.    I did find several BSP references in the library pertaining to both dial pads, and their use on a number of telephone sets, including the 2504.
It also appears that some of the additional components that may have been present in the 2504-BM at the time of manufacture, have been removed.

I've downloaded the schematic for the 2500-DM, and I'll use that diagram for any future requirements with respect to this 2504 set.

Thanks again Karl & Paul.   

N.B. :  As per the above post, I no longer need a schematic for a W.E. 2504-BM telephone set.   But if anyone does happen to find one, please send it to the TCI Library.

Jeff   

Offline paul-f

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #6 on: November 16, 2016, 03:28:47 PM »
Jeff,

A BSP wiring diagram copy is posted here:
   http://www.classicrotaryphones.com/forum/index.php?topic=17110.msg176491#msg176491

A polarity guard is standard equipment.

Looking at one of the "modified" sets, the main change seems to be replacing the mounting cord with a 4-conductor cord and 4-prong plug.

The set has an interesting switchhook assembly to provide the extra contacts.
« Last Edit: November 16, 2016, 04:02:38 PM by paul-f »
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Offline Ktownphoneco

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #7 on: November 16, 2016, 03:56:53 PM »
THANKS VERY MUCH  Paul !     This just saved me a whole lot of work.     Whoever re-wired the set, had just made the necessary changes in the wiring, and stuffed wires all over the place.   Yesterday, I figured I'd clean up the "spaghetti factory" look, and took everything apart, assuming (WRONG) that the switch hook color coding would be the same as a 2500-DM hook switch, with the additional conductors used in the 2504-BM switch hook being given additional color codes.    Once it was all cleaned up, with all of the extra wires from both the hook switch and T/T dial being re-insulated, bundled and stored under the dial pad and out of sight, I put everything back together, and plugged the set in to test it.     Of course it was "dead", and I've now discovered the color coding on the switch hook conductors are "NOT" the same as a switch on a 2500-DM.    As you were probably in the process of posting the 2504-BM schematic, I was sitting here with the switch hook out of the set and with my ohm meter, sorting through the switch conductors, noting which were open and which were closed in both the on-hook and off-hook position, so I could re-connect the switch to the network and get the set working correctly again.
With the correct schematic, I can now do that in a fraction of the time.     The next time something like this comes along, I'll be very careful to write a rough schematic of my own before I start disconnecting wires.    This set uses a standard 2 conductor modular line cord, "Tip / Ring" with a normal RJ11 on the end.
Thanks Again !!

Jeff
 

Offline paul-f

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Re: Wanted - Schematic Diagram For W.E. 2504-BM Desk Set
« Reply #8 on: November 16, 2016, 04:13:20 PM »
You're welcome, Jeff.

I'm glad the timing worked out well.

Sorry for the print quality. The original was obviously a copy of a copy (of a copy...?). It required repair to several of the lines, but fortunately the components weren't damaged.

Hopefully we'll eventually get the full BSP with a set description and 4-wire connections.
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