Finally Got A WECO 555

[TelePlay]

If the buzzer was replaced around 1985, then it seems likely that the 1982 listing for the New Fredrick Hotel is the right one.

If that's the case, it's not there anymore. Demolished in 1997. Was a 10 story building. It was demolished to make way for the Charles Evans Whitaker Federal Courthouse.

     https://www.emporis.com/buildings/177426/frederick-hotel-kansas-city-mo-usa

[unbeldi]

The latest modification date of SD-66520 for the 555, that I have found, is August 1972.  Does your PBX not have schematics glued to the inside that show the date of modification ?

The 555 was certainly still marketed about that time, but had somewhat different appearance by then.

A hotel certainly seems like a probable environment for having a mezzanine, but I believe I have seen law offices with such features.   The address of that hotel was also just a couple of blocks away from the McGee central office.

[Fabius]

Nothing on the backboard and actually looks like nothing was ever there. I searched again and I found a 1972 date on what I think is a capacitor. The reverse directory spells the hotel as the The New Frederick Hotel while the info on the site spells it The New Fredrick Hotel.

[Victor Laszlo]

"I was wrong, the WE 555 was ONLY used as a PBX. I musta been 'membering wrong. Sorry for the confusion."

Thank you for the updated information.

[Fabius]

This board has cable tied down on the wiring blocks which has Amphenol  connectors on the other end. Where Amphenol connectors used on 555 boards from the very being of 555s being manufactored or at a later date?

[Alex G. Bell]

Definitely not.  Amphenol (57 series "micro-ribbon" type) were first used in the Bell System on 560 series key telephone sets, field trials I believe by NY Tel with F-series numbers instead of the conventional 560 codes.  I doubt 57 series connectors even existed in the late 40s when 555s first came out.

Another reason PBXs were probably never used for public exchange service: charge supervision issues.  A call initiated to a customer on any manual CO swbd must not have charge supervision until the called station answers.  A 555 has no provision for the operator (attendant really) to answer an incoming call from another exchange and get the order for the called local line without causing charge supervision to the calling customer.

[Fabius]

I obtained a power supply for the switchboard. Model 550005 made by Power Controls Inc in Connecticut. In fact I got two of them. One is branded Executone and the other is Isoetec which was bought out by Executone. I emailed the company and asked if they had any documentation on this model. Maybe there's info in the TCI library. Or does anyone have any?

[unbeldi]

You also need a supply for ringing power, unless you are happy with using the hand generator.
For this reason, the key system supplies are very convenient to use if 24 volt talk battery is sufficient.

[Alex G. Bell]

You also need a supply for ringing power, unless you are happy with using the hand generator.
For this reason, the key system supplies are very convenient to use if 24 volt talk battery is sufficient.

Many 555s were powered from a 101G key telephone system power plant, which used a selenium rectifier for the 18-26VDC filtered TALK battery supply. 

555s are rated to operate from 16-50V with appropriate voltage lamps installed in SD-66520-01. 

In large cities 555s were often powered from the serving CO, to which the trunks went, via cable pairs providing DC voltage and ringing.  As discussed in the related BLR article, they were explicitly designed to operate over a wide voltage range and at minimum operating current to optimize this kind of operation. 

This was a practice introduced with earlier manual PBX switchboards when many cities did not have commercial AC power because converting commercial DC power to operate telephone equipment was problematic.  The power conversion equipment needed to use motor-generators, which had a high maintenance requirement.

Most versions of the 101G also included a 20Hz ringing supply using saturated core magnetic devices to derive 20Hz from 60 Hz AC line power with no moving parts.  101Gs were superseded by the 20- and 30-types which provide 30Hz ringing rather than 20Hz and were generally not used to power PBXs.  The sound of ringers operating from 30Hz ringing current is quite different since the clapper operates 50% more times.  20Hz is more pleasant sounding.

I know someone who had and probably still has some 101Gs he'd like to sell.

I suggest uploading a larger version of the Power Controls power supply photo rather than the tiny 225x169 thumbnail so that people can read the specifications.

[Fabius]

You also need a supply for ringing power, unless you are happy with using the hand generator.
For this reason, the key system supplies are very convenient to use if 24 volt talk battery is sufficient.

I should of specified that this power supply supplies 24vdc, 48vdc and 90vac. So I should be okay with the ringing.

[unbeldi]

I should of specified that this power supply supplies 24vdc, 48vdc and 90vac. So I should be okay with the ringing.

Ah, you're right.  I looked it up, but didn't see the ringing output, sorry.

The supply only provides 1 A on the DC outputs, ea, so you may need the second unit, indeed, if you want to run your street on the PBX.


Input: 120VAC, 60Hz, 1A
Output:
 48 VDC, 1A
 24 VDC, 1A
 90 VAC, 5W, 30 Hz

[Fabius]

Find another 1972 date on a tag as shown below

I am now looking for where to hook up the power supply. From what I read it is on the terminal block to the right? That one has a connector on a relatively short cable wired to the wire block. One of the connector leads goes to a lug on the metal frame (ground?) Does the connector plug into a power supply? if so which one? Thanks.

[Alex G. Bell]

Find another 1972 date on a tag as shown below

I am now looking for where to hook up the power supply. From what I read it is on the terminal block to the right? That one has a connector on a relatively short cable wired to the wire block. One of the connector leads goes to a lug on the metal frame (ground?) Does the connector plug into a power supply? if so which one? Thanks.

The power supply connections are not normally connectorized.  The power connections appear on a terminal strip at the base and are shown on the SD.  Do you have SD-66520-01?  It should be in the TCI library.

Page G2 Fig. 54 shows battery and ground terminations on the MISC. terminal strip:
BAT = term's 1, 2, 3 & 4
GRD = term's 45, 46, 47 & 48
+/- RINGING = term 22
RINGING GRD  = term 24

However there are some strapping options on this terminal strip so without knowing what's there it's impossible to say with certainty that it will work with just these connections.

There is an 8 pin Cinch-Jones plug like the one in your photo except chassis mounted, on the back of the 555 TEL unit and a 10 pin one on the front used to connect the dial lead connections from the terminal block under the dial mounting, and the headset jack leads, to the TEL unit.

BSP 536-550-210 para. 3.07 forward discusses grouping of multiple positions.  The 8 pin plug on the back of the TEL unit is for that.  That might explain your cable if it ended in a socket rather than plug but so far I don't see anything about a plug ended cable.

However regardless of that, the gender of your mystery plug is wrong to plug onto the TEL unit and I can't see from your photo where the other end of the cable terminating in the 8 contact plug goes.  Where does it go?  It seems unlikely someone would have connectorized the power with a C-J plug since that would require soldering the plug terminals in the field.  I'd expect a 25 pair cable to be used with multiple pairs paralleled to reduce feeder resistance.

If you need assistance interpreting SD-66520-01 just say so.

[Fabius]

The mystery plug goes to the wire block right where it is labeled AUX

[Fabius]

There are 4 terminal blocks marked stations, trunks, aux at the bottom. Where would the terminal block for power be in relation to them?