Continental AMI Juke Box Fault Finding

[rob1948]

Hi Norman/Ron, I am back again. I lifted the entire JB mechanism out of the cabinet high enough to access and remove the magazine motor. I have stripped serviced and re installed, all good. I removed the scan unit but first locked the sprag relay, removed the magazine cleaned and re lubricated the shaft and re assembled. My DeoxIt spray arrived from America and I have sprayed all the contacts and slip rings. Now to get it working !!! This is where I am -- Record Selection- Letter Buttons lock in , Numeral buttons do not, but holding it in the search wiper motor operates makes the selection but the selection solenoid is not operating the pin pusher ?? Something not working in the scan control, magnets not energising, scan switch not closing Also the latch solenoid resistor gets hot ? Can you please advise. Thanks Rob

[jukenorman]

Hi Rob,
If the number buttons aren't latching, that's probably down to an adjustment on the latch bar operating rod (Pages SSS-7 & 8). When you say "makes the selection", do you mean that the sprag relay operates? In conjunction with the sprag relay operating, the pulse control relay (R2) is held energised on a time delay - this is what ensures that a "fat pulse" goes to the selection solenoid. Are the time delay components, especially the 100uF capacitor, on R2 OK?

The latch solenoid resistor is rated at 20W, big resistors like that do get hot!

Norman.

[Ron Rich]

Hi Rob,
Operate your latch solenoid manually (power off)-- if the number buttons won't latch, it is a mechanical problem--
By saying "--makes the selection--" are you saying the sprague relay stops the wipers from searching ? Ron Rich

[rob1948]

Thanks Norman and Ron, Thanks for your replies. Let me follow up and re check as per your comments. Rob

[rob1948]

Hi Norman/Ron, First of all just some feedback re my very first post regarding my transfer motor problems with my AMI Mono JB.(A gear shaft in the gearbox had sheared off). I have replaced the GB and set it up as per the service manual instructions. I am please to say JB is once again working fine.

With regards to the posts above, I have adjusted the automatic selector ensuring correct relationship between the ends of the metal push button switch shafts and the plastic push buttons. All buttons now lock in and release when a section has been made. Search wiper motor operates until selection is made and then stops', Sprag' relay operates, pulse control relay operates(very briefly). Scan control magnets do not pull in and the selection solenoid is not operating the pin pusher ? I have not checked the R2 100uF capacitor as you suggested Norman, but the selector solenoid was operating before I removed the magazine, pin pusher assembly and search unit to lubricate the magazine shaft ? I did however lock the sprag relay and marked the position of the pin pusher before disassembling.

If I push a selector pin in and lift the magnet plate in the scan control unit then the record magazine turns, the selected record is picked up and placed on the turn table, the tone arm moves onto the record but then immediately lifts off and the record is placed back into the magazine ? I am also trying to 'trouble shoot' using my other AMI JB. Any suggestions please .Thanks Rob

[Ron Rich]

Hi Rob
I am ASSuming/guessing here-- It sounds to me that you have a weak PS somwhere-- If you have not done so, change ALL of the electrolytic & "paper" caps, before doing anything else . Ron Rich

[jukenorman]

Hi Rob,
The pulse control relay should stay energised for 100 milliseconds (capacitor holds it in) so it's either going to be the capacitor or contacts on the sprag relay or pulse control relay that's preventing the selection solenoid from operating.

With regard to the transfer motor not stopping when a record is placed on the turntable - is the selection pin being reset? If the pin is not being reset, this is down to cam switch 6 - is it operating? If the selection pin is being reset, that would point to a faulty stopping switch (assuming the reject switches themselves are not the problem!)

Norman.

[rob1948]

Hi Norman/Ron, Thank you for this feedback. This gives me something to work with. Rob

[rob1948]

Hi Ron/Norman,
I have bought a new 100MFD DC capacitor(on the terminal strip assembly in the search unit)for the Pulse Control Relay but have not yet installed it. However the PCR activates the Scan Magnets and together with the scan switch turns on the Record Magazine Motor, and the PCR at the same time activates the Selection Solenoid. So if I manually operate the PCR then the Scan Magnets and Selection Solenoid should energise ? If not then the problem will be with the PCR contacts ? Is my reasoning correct? I have also cleaned both the Sprag Relay and PCR contacts and sprayed them with DeoxIt 5.Thanks Rob

[jukenorman]

Hi Rob,
No it's not that simple - the PCR and the Sprag are operating together. The PCR is being held energised on a time delay (this is where the 100uF capacitor comes in) after the Sprag energises which is what guarantees a fat pulse to the selection solenoid. The operation is covered in the manual, pages SSS-23 to 27.

Norman.

[Ron Rich]

Hi Norman,
Izzit still OK to use the word "fat" (pulse) ? I dono-- watch out for the PC Police ! Ron Rich

[rob1948]

Hi Norman/Ron
Thanks again for your response(s).Let me now go and change the 100mfd capacitor on the PCR. Should I also change the .05mfd DC capacitor on the Sprag Relay. If so should I increase the size of the capacitor while I am about it ? Maybe a 1mfd or bigger ?? Thanks Rob

[Ron Rich]

Rob,
No-- the .05 is probably an "anti spike" cap-- use an .047 at the correct, or higher voltage. Ron Rich

[jukenorman]

I picked up the term "fat pulse" from Rock-Ola manuals; I think it's quite descriptive!

Norman.

[Ron Rich]

Hi Norman,
Yes-- I do recall it being in a manual-- but my great, but not too long memory filed it, in the AMi section ? Ron Rich