Wurlitzer 1100 Jukebox  Repair Journal: Page 2
By Chad Hauris, 10/29/05

The Wurlitzer 1100 uses a single motor to operate all functions. The selection cycle begins when the override switch is activated by the wobble plate. There is a detented gear at the back of the heart-shaped selection cam that releases, and the cam causes an arm to scan up and down on the back of the record rack. When the crank arm hits the selection pin, the transfer cycle begins. The scanning arm stops at the appropriate record and the detented gear is held in place by a pawl to keep the mechanism at the appropriate place.

Then, another part of the selection arm swings the tray out to the play position. Once in position, the turntable rises through the tray and lifts the record off the tray. As the turntable reaches the top, it pushes the tonearm off of its rest. When the turntable reaches the top, it begins to turn through a worm gear and clutch arrangement and the record begins to play. When it reaches the end, the tonearm trips a switch to activate the reject solenoid, and the record is put away. If another selection is in the memory, the override switch keeps the motor running, and the cycle begins again on selecting the new record. If no more selections have been made, the motor shuts off.


Here is the heavy-duty mechanism motor.

On our initial test, performance was pretty good, but there were some problems. One is that the motor was shutting off before the tray was completely inserted. This was solved by adjusting the cam which controls the motor shut-off switch (located at the front of the machine).

We decided to next examine the electrical wiring in the junction box. It appeared that it had the original power cord which was very brittle. We removed the 15 amp fuseholder from the circuit and installed a new grounded power cord, plus a 5 amp fuse for the main power and a 2 amp fuse for the control transformer. We grounded the green lead of the power cord to the junction box chassis, then ran ground wires to all other components.


Here is the junction box before the re-wire.


Junction box with new wiring and fuseholder.


Here is the old fluorescent ballast from 1947! We have observed cases of ballast melt-downs, shorted ballasts, and brittle wiring, so we always replace ballasts in each unit. This one was functional, but we wanted to avoid future problems. We always add a 1-amp fuse to the ballast circuit for additional overload protection.


Here are the new ballasts (the original unit contained 2 coils) mounted to the bracket inside the front door. This door and bracket are grounded for additional safety.


Here are the lamp sockets that light up the bottom of the front panel. We could not find any comparable new sockets so we had to rebuild these. We unsoldered the old cloth-covered wire and soldered new leads to the sockets.


Re-wired lamp sockets.


Lamp sockets installed in front panel. We used compact fluorescent bulbs for longevity and low heat output.

After improving the electrical safety of the unit, we noticed some performance problems. One major problem was that the selection mechanism was jamming when the selection arm was at the bottom of its travel. It would jam at the bottom and only play, say, record #14. To remedy this, we disassembled and cleaned the sliding selector mechanism and the record magazine, and re-lubricated them with Hammond organ generator oil. Two failure modes were at play here: sticky old lubrication, and insufficient re-lubrication after cleaning. We remedied both defects.

We'll have more on the mechanical work in the near future.


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