AMI/Rowe Jukebox technical tips
Last update
November 24, 2011
Rowe Transistor Cross Reference PDF - thanks to Erwin Boot (Flamingo Records/Auto. Music Co. AU) for this list!
When
first looking at an older AMI/Rowe jukebox (prior to 1970's) the very first item to be checked is the condition of the electrical cords within the jukebox AND the power cord for signs of deterioration. The "lamp" cord used in most of the 40's to 60's models is breaking down by now and you will see at the plugs or on the wire itself that pieces of the insulation are shattering off. This is both a fire and safety hazard! You MUST replace any brittle wiring within the jukebox! This is a relatively easy job as this wire is normally just used for the lights and the amplifier, and can easily be traced, and replacement wire installed.
As for the power cord, be sure to flex it close to your ear and if you hear any crinkling sounds from inside the wire cable, then it too MUST be replaced.
Common problems with the AMI jukeboxes - including the Continental series - include:
Gummed selection pins due to the use of oil or WD-40 - these are not to be lubricated!
The wiper ring blades that connect the ferris wheel drum electricals to the machine are dirty.
The microswitches that control the selection and cancel of the pins are faulty.
The cam switches (blade style for the A through K, microswitch after) are faulty - common symptoms are 8/10A Slo-Blo (1A Slo-Blo is OK, nothing higher please!) fuse pops and the gripper motor is jammed. Clean the cam switches carefully, do not lubricate with ANYTHING. Polishing the contacts with a burnishing tool or very fine file - you want the contact faces to shine enough to reflect your face!
Symptoms/Problems:
Slow gripper motor. and/or rotation of ferris wheel -check for 24VDC at the motor when the motor is running, it should be no less than 24V. If it is then check the bridge rectifier in the transformer/fuse box, if it is a Selenium Rectifier (a series of metal plates on a central shaft with three or four lugs that wires are soldered to) then you probably need to replacc it with a modern Silicon Bridge rectifier (10A/100PIV minimum) taking care to match the negative and positive and AC terminals to the old part. I'll post some pictures the next time we do this conversion... Some folks are still making these.
These pictures show various test points and assemblies used in the Ferris wheel style Rowe/AMI jukeboxes.
This is the side A / B rocker showing the spring assembly if you've taken it apart and can't recall how it goes back together...
    
Here are the !@#$! cam switch blades...I dismount them for ease of cleaning... checking alignment carefully when putting back!
    
Here are the wiper blades and their rings, you can see these from under the front of the mechanism towards the center....clean the copper rings with an ink eraser and check that the wipers have some pressure on the rings once remounted.
    
Check the microswitches with an ohm-meter. The readings should be steady once the switch has 'clicked' (either way). If the reading bounces then I suggest you change the micro-switch.
    
For the folks new to multimeters about the safest use you can put them to for servicing jukeboxes is the Resistance tests. These are all best done with the jukebox unplugged. You simply need to gain experience in reading resistance across contacts of switches, microswitches, and blade switches/wipers to learn if they are working correctly or not.
It is very important to have a good connection between the probes of your meter and the item you are testing. I recommend using a healthy pair of alligator jumper wires that with one end on each of the probe tips, and the other to grasp the lug of the switch in question and read the resistance when the switch is both open and closed.
A point to consider when testing switches is if the switch is still soldered into the circuit when the switch is open it still may indicate a short as an switch somewhere else in parallel with it may also be closed (cancel circuits for example)
I am using the convention that the letter "R" is used to indicate the period place holder when measuring resistance.
With an ohm-meter (resistance) set to the lowest setting (200R or less) a good switch will show about 0.2 ohms (0R2) resistance - remember to check the lead resistance first and to mentally subtract that from any reading - probes shorted should show about 0R2 to 0R4 (ohms).
PDFs now available for the AMI Model D: R-200 Mechanism Service Manual (D-40) This needs to be printed on Ledger size paper - 11" X 17" and then folded. 3.66mb in size...
Full copies of most of the early AMI manuals are available from us for $25 - $35, email the model you need.
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