Jukeboxes, AMI to Wurlitzer

I took the pinbank from a Rock-Ola 1493 apart to fix a sticky pin - I got the pin fixed but now I can't get the thing back together! With both sides removed the pins will toggle to positions either too wide or too narrow to fit the slots in the cover. Anyone know a good trick for aligning the pins so that the first side can be re fitted?

However I would not like to take one of those apart! What I use is MG Chemicals "NuTrol" control spray. I spray the stuff on, then work the pins (all of them) back and forth a number of times (10+), then a second spray, rework the pins. This works for ALL pinbanks - both Seeburg (M100A to the tormats) and Rock-Ola. This fixes intermittent selection (pin flips on early machines but the magazine won't rotate due to dirty contacts on the pin wiper switch) and sticky pins. I've been doing this for over twenty years and the results are very long term - in ALL cases my customers do not have a problem for a minimum of ten years and some have never called me back for a pin bank issue.

Initial service tips

As with any electromechanical device, a simple thing to check first is all the switches and microswitches with the aid of an ohmmeter. Look for switches that do not go down below 1 ohm in resistance AND/OR bounce all over the place when closed (details below). I find that this process, if done carefully, will find most of the problems in a jukebox. You will probably need a burnishing or points file to take care of switch contacts on the keyboard, also some "Tuner Spray" or contact spray cleaner applied to the keyboard internal switch will often help. Lastly, if your Rock is one that has selection system that scans on a pin being moved, then you also spray those pins and work them back and forth to improve the contact there. DO NOT USE WD-40 or anything other than electrical/electronic rated contact spray. We carry a good grade of contact cleaner. As for oiling, Home Hardware (or the equivalent in your home area) might carry "ZOOM-SPOUT" oil, this is very good for jukeboxes as it is a paraffin based oil and evaporates with no sticky residue, and it has a nice pull out tube for those awkward corners. We also sell this oil.

Motors

Problem: Noise coming from speaker when record is picked up or replaced in the magazine by either Rock-O-La or AMI jukebox.

Possible solution:
This noise is coming from the gripper motor, you might find that the brushes are badly worn OR that the commutator elements are gummed up with carbon worn from the brushes and held in the grooves with a bit of oil that has leaked around the bearing. I take those motors apart and clean the commutator with a burnishing tool (used in EM pinballs and old car/motorcycle points), this thin polishing tool fits perfectly into the grooves of the commutator and careful scraping will clean them out and the motor should generate less electrical noise and arcing.

Overhauls: what I do is TEST every single microswitch in the jukebox with an ohm-meter. Each circuit that is used MUST trip to 0.5 ohms (or less) and not exhibit contact bounce (the reading changes as you depress the actuator).

I test these with a pair of jumper leads with alligator clips. First short the alligator clips so you know what the '0' reading is. (Often this will show as, say, 0.3 ohms up to 0.9 ohms. This is your "Zero" reading. Subract this (0.3 for example) from your test measurements. Check the "Zero" from time to time to make sure it doesn't drift without your compensating.) Then clip the alligators to each slip on connector for Common and N.O. (Normally Open) and then actuate the switch SLOWLY. When you hear the click the reading should drop to 0.05 and stay there the further you press the actuator until it bottoms out, then slowly release the actuator. Again the reading should be stable. Slight jumping is OK as long as it does not go above 1ohm. Now repeat for Common and N.C. (Normally Closed) but here (hear?) you will start with a short and the switch then opens as you actuate it to the click point. It MUST NOT SHOW OPEN UNTIL YOU HEAR THE CLICK!!!

The starting resistance on the C to N.O. might be anything higher than 10 ohms (coils etc in the circuit) so ignore that, same with the C. to N.C. when it opens it might only go to around 10 ohms (instead of infinite - but it IS in circuit still after all!).

These readings are all relative to your '0' reading so if your '0' reading is 1.0 ohms then a pass is 1.5 ohms.

I don't like to recommend that non-technicians solder the wires directly to the lugs, rather I recommend that they just replace any connector that is loose. I see too many units soldered with plumbers solder (acid core!) or solder paste etc...this stuff works it's way into the switch and leads to early failure.

Any switch that fails this test is replaced. Interestingly enough I find the odd NEW switch fails this test as well.

If you talk with your ISP (Internet Servie Provider) you should be able to join a jukebox newsgroup - alt.collecting.juke-boxes - a good resource to search through for questions about your machine. www.googlegroups.com is another access point to this and other groups - but not as favored by the experts. If you have a MAC running OS X then I recommend you check out Panic's "Unison" maill reader, my favourite. For PCs then the only one I can recommend is Forte's "Agent (Free Agent is good enough for most folks)"

eBay.com migh tgive you an idea of what a machine like yours sold for recently if you need to get an idea of it's worth, remember that eBay is totally unregulated other than feedback and there are scammers operating out there!

You can also join the jukebox mail-list where both collections, owners and dealers in jukeboxes gather to exchange tips, questions and solutions.
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