Rockola 440 Question

Hello folks! I have a question regarding a Rockola 440 that I am renovating. I've made some great progress on it thus far and it is working very well! (most of the time...). Here's the scenario: Selecting the "A" side of selections is working very well. However, the "B" selections are not working (most of the time, every now and then they will work. I have made a few adjustments to the write-in carriage and it stops at the correct selection and lines up very well with the write-in pin (selecter lever). The hammer solenoid/coil doesn't fire when I do a "B" side selection. I can push the hammer down manually and the correct selecter lever clicks into place nicely. I pulled and checked the solenoid coils and they work just fine outside of the unit.

I do have the service manual for the 440, but am having some difficulty identifying what the problem might be. Is it a simple matter of pulling out the selector plate and cleaning the bands and wipers? I have do a good deal of cleaning with the plate installed, and the bands/wipers looks as good as new. I'm not certain where the power burst to fire the hammer coil comes from...

Any help would be greatly appreciated! I'm sure happy with the unit and am looking forward to getting it humming!
Thanks!
Tony

Hi Tony,
I do not have the schematic for that handy--but I would look for a relay, that switches from the A to B coil in the write in circuit. You might also measure the two coils (with power off), as the B coil, itself my be open ?
Ron Rich

Thanks Ron!
Yes I did find the relay in question it's dirty, so I'll clean the contacts. The relay is working - interesting I have never encountered a light bulb used to limit current!! It was burned out, so I replaced it and it illuminates briefly when the relay fires. I'm assuming there since it is a dual write-in carriage, there are two hammer coils for the B side - one on each arm. Now that I think of it, my intermittent issue would be solved in that once in a while I get lucky and a few side B's work! I'll check all of them to see if any are open.

Assuming a bad hammer coil, where would a guy get a replacement? Or do I wind my own (yikes...)
Thanks again!
Tony

Ron, one more question - can you recommend a good way to test those hammer coils? Simple continuity with the unit off, or will it pick up continuity from somewhere else. Pull one of the wires?

Hi Tony,
Pulling a wire is the "for sure" way--it may be possible to get a "wrong" reading if connected---
Ron Rich

Thanks pal!

Hi
I would check the resistance of the coils,
is one end of the write in arm working with the B sides and the other isn't?
if the write in arm starts to rotate when a selection it means the selection has been made and the write arm is looking for that particular contact, no harm to clean the slip rings on the wobble plate and the write in contacts
the bulb flashing is normal and is a current limiting lamp,
check the wiring on the write in arm just in case anything has come loose especially where the wiring is attached to the solenoids
regards
clones

Thanks clones,
Both the A coil solenoids are firing just fine. It appears that the B side work intermittently (I'd rather just have them NOT work!). I'm thinking the "write" circuit relay on the power supply is sloppy. It's pretty dirty and the contacts look pretty bad. I am going to pull the supply out and clean up the relay and hope for the best. I did test the hammer coils and they all appear to work well with none of them open.

I've also realigned the dual write-in carriage per the user manual the best I can. Everything seems to line up well for a while, and then it comes out of alignment again, either striking one selection off, or striking 2 simultaneously, or striking nothing at all. This machine was in a bar and played non-stop for a lot of years - there are over 60,000 selections on the counter (and still working!) and I think everything is just pretty darn worn to the point there's probably some play in about every moving part!

I did make one little modification and am re-purposing the coin return button to slide a magnet across a NO/NC/C reed switch - I wired it in place of the credit slide switch (which was shot). So I can hit it without needing to open up the unit. I'm assuming that when errors build up, the credit reset is necessary? Not sure about that one, but it made sense to me at the moment... A few errors here and there don't bug me too much, but it sure would be nice if I could get it working a little better! It looks great! Lots of new artwork, custom song labels, new ballasts and lights - it's really quite a show piece!

I'm quite the newbie here, but I'm having a blast working on this 400 pound iPOD! Thanks for all your help guys!