W4-L56 wireless wallbox

[steveb]

I came across an original and complete W4-L56 but don't have any information about this type of wallbox except that it was made about 1946.
How does it communicate with a jukebox?  Which boxes?
Where does a power cord connect in the wallbox?
What is the key number so I can open it?
Thanks for any information.
Steve

[steveb]

Hi Ron,
I thought you might know something about this Seeburg wallbox from the mid-40's. I don't intend to get it functioning but would like to know how it was suppose to communicate with the jukebox.
I'll probably restore it cosmeticlally and have it light up, then put it on display.

[Ron Rich]

I have no idea(s)-- purchase the Service Manual for the M146/7/8 Phonograph--I believe it's covered there--if not, there is a dedicated Service Manual for it--check with the suppliers listed in our FAQ's section. Ron Rich

[robnyc]

Hello Steve, I have one of those boxes on the dining rm table.

It uses two 7-pin tubes (IIRC) they are 6C4 triodes. One is connected as a diode to rectify the power for teh other which is a 250 KHz oscillator. the system distributes through the power line. This is called 'carrier current". Many college radio station use this method as did my quasi-legal setup when I was 10-11.

The oscillator is modulated, it is just key-down each time the wiper grounds in the box. The juke just receives this and uses it to fire a thyratron tube to pulse a stepper.

As for key, mine is S368 which likely means that each box had a different number within all three digits -just like later boxes. These are triple-bitted so if no number is stamped on the face of the cylinder, it probably is an op's key and you'll be stuck drilling it out.

Personal opinion; this was an OK idea if all you wanted to was to add a wallbox or two to serve a room outside the main room where the juke was located, but it did require 120vac at each box. From a legal and code standpoint, it meant that an electrician was needed and wiring was to be in BX or conduit. Hardly practical for a diner and such. Then, one also has all the tubes and circuits associated with the receiver.

They may have been around before WW-2 but as far as I know, these came and went with the trashcan series and never reappeared.

If you rebuild the box be sure to either change the small filter cap or remove the tubes from their sockets. No point in risking the transformer with leaky cap.

RobNYC

[steveb]

Hi RobNYC,

I was able to open the wallbox and discovered the following.

- There is a small transformer with two wires in the space where I thought a larger step down transformer for 125/25 v. should be. It looks to be original and is screwed down in a bracket to the case frame. It does have a connection to the line voltage input block and to the 135 ohm 5 watt resistor for the lights. Any thoughts about this transformer?

- Both 6C4 tubes were missing.

- The oscillator coil in the metal shield had white fuzzy crystals around the coil. Does that indicate it is damaged?

- The coupling capacitor that is held in the bracket has one of the wire leads clipped. Two wires go to the oscillator coil and one goes to the service switch. Why is one lead clipped?

- I disassembled the interior components and serviced the motor, selector switches, contact disc, coin drop. I connected the motor to a 25 volt transformer and it runs fine.

As I mentioned in my earlier email I just plan to repaint the case and have this light up as it sits on display. But I would like to know about the above findings if you have any suggestions. The missing tubes are not an issue.
Thanks,
Steve

[robnyc]

Steve, it is a small transformer, not much load. It is possible that someone converted that box to direct wire.

The oscillator coil in the metal shield had white fuzzy crystals around the coil. Does that indicate it is damaged?
-That is just fungus on the coil doping. You see that on old equipment stored in damp locations.

I shared a car with someone who was sick and get my first bad cold in nearly ten years. When i feel a bit better i'll take a look in the box i have here.

Regards,
Rob

[steveb]

Hi Rob,
Hope you are feeling better by now. Finally had a chance to follow up on this project.
Were you able to take a look in your .W4-L56 wall box? I still have a question about the clipped capacitor lead and where the internal connection for the power cord goes.
Thanks,
Steve

[robnyc]

Steve, i managed to extract it from where was, let me know the questions. It is probably easier to take pic's when I answer.

Rob

[steveb]

OK Rob.  I'll send a PM with pics.
Thanks.

[steveb]

Hi Rob,
I finally reassembled the wallbox and powered it up. I can trace the 120 volts through the circuit but I am not getting the 25 volts as indicated on the schematic. If I disconnect the 120 v. and apply 25 volts from an external transformer I can trace the circuits to the credit coils, motor, relay, etc. and they all function. Similarly, if I apply 6 volts I can get the lamps to light.

As mentioned before the transformer has only 3 wires, one is grounded to the frame and one is connected to the 120v input. The last wire is connected to the lamp circuit.

The transformer does not show signs of overheating and testing shows the following resistances:
Ground to 120 lead 5.6 ohms
Ground to lamp lead 1.2 ohms
120 lead to lamp lead 4.8 ohms

The ceramic resistor measures 135 ohms as per the schematic.

Other than a bad transformer, can you suggest why I do not get 25 volts. And can you again explain why the transformer only has 3 wires when the schematic shows 4 (2 for 120 input and 2 for 25 v output).
The tubes have been removed.

By the way, I found a 1944 silver quarter stuck in the mechanism.
Thanks for your suggestions,
Steve

[robnyc]

Steve, that box has been modded for wired operation -not wireless. One clue is that they would -never- wire the chassis to line on either side.

if you have the schematic, you can probably at least wire it to power it's lights and motor based on the internal tran.

here is a pic of the terminal connections as original -just two wires: www.flickr.com/photos/90641375@N06/45823279221/

Rob