AMI Contiential II selector problem

[ab]

I have had this jukebox for 20 years and have worked hard to keep her in top top condition but I have a problem that stumps all the experts I've talked to about it. I have cleaned the wiper boards and the wipers, I have cleaned all the contacts on all the letters and the number selections as well as the sprag relay etc but in spite of that I have a problem. When I punch in any selection between B-7 and B-10 it will not lock in the selection, the very problem occurs on selections J-7 through J-10. on these selections the wipers just keep spinning and will not lock in. Here's the mystery, every other selection on the jukebox works perfectly and locks in immediately. In other words it couldn't be the letter B button that's the problem because B-1 through B-6 works great and the same goes for J-1 through J-6 works every time. Likewise the numbers 7 through 10 work perfectly with every other letter with the exception of B & J. I know that alignment is critical on these machines and I worked diligently to achieve a dead on adjustment. In my mind since only eight selections are failing seems like that would rule out alignment but correct me if I'm wrong. Something else I noticed that I don't understand but perhaps someone else will is there have been times when these selections would work or partially work. I've seen occasions where for no reason I could hear it punch in the selection as it passed the correct segments (which would play the record) but the wipers did not stop spinning and the buttons did not release. On a few occasions I have seen it punch in the selection and the wipers actually stop where they are suppose to but you could still hear the selector wanting to spin (like it was hung up) and the selector buttons did not release. In most cases, like right now the eight selections will not punch in at all. If anyone can understand what's happening please share cause me and everyone I've spoke to is totally perplexed by this problem

Thanks for any assistance

Alan Burton

[Ron Rich]

Hi
Alan,
My GUESS would start with the motor that powers the wipers-- is the clutch operating as it should (ie: is the motor properly oiled ) ? Next I would clean the contacts as described in our FAQ's section, using Dexit-5. Unless one or more of the "wiper tips" has "gone missing", I sure would not attempt any adjustments ! Ron Rich

[ab]

I don’t think it’s the motor or the wipers. If that were so the other 95% of the selections wouldn’t play properly every time. I already made a dead on adjustment. That’s the mystery the same buttons, the same wiper board, the same wipers, same everything are common to all the other 90+ selections that work perfectly.

[jukenorman]

I also think you need to clean contacts as Ron suggested. Your logic above is slightly flawed - for example, the B button contact operating at a hypothetical 60% efficiency might be able to pass enough current to pull in the sprag relay when used in conjunction with a number button contact operating near 100% efficiecy. But a selection (B7) where both contacts are a bit dirty might current limit enough that the sprag relay will not pull in. That it's always B, J, 7, 8, 9 and 10 supports this.
Norman.

[ab]

That kind of logic is where my thoughts were taking me. For the record I cleaned and polished the wiper boards very well. On the selector buttons I sprayed them with contact cleaner and then used a contact cleaning tool on the make contacts for every button and letter. I would even push down on the button slightly to increase the pressure a little on the contacts to clean them better. I even took a VOM connected in front of the buttons and letters and depressed each one and checked continuity from each letter and number to its location on the respective wiper boards and saw no difference. I even checked to see for example that each letter read all the way through the inner conductor ring over to the number board. Still eight selections won’t play. Have I left anything out or is there something I can do better. Please advise and I’ll try it if I can. Thanks for all the replies.

[jukenorman]

Hi Alan, if you're happy that you've cleaned the contacts to your satisfaction that's fine! The only other thing I can suggest is to manually align the search unit to B7 and briefly short the input of the letter wiper assy to ground to see whether the sprag relay pulls in on B7 or whether the search motor runs and it pulls in on B11. That should give you an idea whether your problem is on the search unit or the pushbuttons.
Norman.

[ab]

Thanks Norman I like that idea. If I understand you’re saying I should manually set the wipers to letter B and number 7 and then temporally ground the (B) segment on the letter board. So it’s a ground connection that’s provided through the letter buttons, is that correct? If I’m reading you providing that ground would them simulate pushing the letter (B). So would I need to push the number (7) button down before grounding the (B) segment? On the other matter concerning B-11, I have a 100 play box so I don’t have a B-11.

Thanks for assisting me

Alan

[jukenorman]

No that's not quite what I was suggesting. I was splitting the circuit in the middle, bypassing the buttons altogether so you would be grounding at the input of the letter wiper on the search unit where it connects to a normally closed contact of the sprag relay in series with the motor control relay. I'm not that familiar with 100 selection Continentals but I think the search unit would be the same as 200 selections so it might well attempt to select B11 even though there's not a pin to push. What you're suggesting is broadly similar though, and could be the next step?
N.

[ab]

Norman I hate to sound like a dummy but when you say ground the input of the wiper just exactly are you talking about. On the solder connection at the (B) letter segment, on the inner contact ring on the letter board, or momentarily try and ground the letter wiper it’s self.

[jukenorman]

I don't think there's anything in the manual to clarify it. I'll try to take a look in a search unit later today. Because the input of the letter wiper is connected to a sprag relay contact, it should be quite accessible.

[jukenorman]

Hi Alan, I'm sorry - I have misled you here (and misled myself somehow)! I was referring to a Continental pdf that I have on my laptop (which doesn't have schem-a-grams) but now that I've looked at a "proper" manual, the routing of the ground path to pull in the sprag relay is as follows: switched at credit unit, through the letter pushbuttons, through the letter search unit, through the number search unit, through the number pushbuttons and on to the sprag relay. So I suggest you align the search unit at B7 and ground the B segment on the search unit, see if it pulls in the sprag relay and pushes B7 pin. This is splitting the circuit just about in half and depending on what happens, you either move forwards or backwards through the circuit to see where it's failing.
N.

[ab]

My basic understanding is the letter segments connected directly to the respective letter buttons. When you push that button the circuit is completed to that segment and then connected to the inner ring of the letter wipers and from there it connects to the inner ring of the number wipers. My understanding is which to push the letter it completes the circuit Over to the number segments inner ring where it rotates until it finds a similar completed circuit from a number button and then it latches. So if it’s ground potential that the letter buttons deliver to the wiper board it would seem but if you set the wipers to the B7 position, then push down the number seven button, and momentarily provided ground to the B segment on the wipers it should punch in the selection. Is that making any sense or not?

[jukenorman]

Yes of course, the 7 button would have to be depressed to make a circuit! I'm glad you're keeping me right!!