AMI G-120 found on Kijiji, followed me home

[BrianB]

I wish I had my manual with me!! I restored an AMI F and had a G for awhile. I really like the mechanism and how easy it is to work on.

Did you check the Credit Unit to make sure it has credits registered on it? I would unplug the Credit Unit and remove it and open it to make sure that all is well under the cover. If somebody tried to rig it at somepoint for free play they might have messed with it. My "F" had the same problem.

It works on spring tension, ratcheting and a stacked leaf switch. Do you have a manual?

[cdc1960]

Brian,

thanks for the reply. I do have a manual, and I believe the credit unit is functioning, as the rejector accepts coins, and is "clicking"... I'll open it up for a better look. The selector bank is "dead" i.e no clicking of the buttons when depressed... the turntable is spinning constantly regardless of the DC switch position, so I'm thinking it's the DC voltage supply... I'm trying to figure out what would be a suitable silicon bridge rectifier for the selenium unit...

Chris

[cdc1960]

Any AMI techs out there?  I checked the output on the transformer in the junction box, 38vac to the selenium rectifier. It's producing 31 vdc, and I've got 31vdc out the harness cable socket at pins 1 and 3, and 31 vdc out the mechanism cable socket at pins 1 and 4. That's the odd thing, I checked the entire junction box against the wiring diagram, and pins 3 and 4 at the Mechanism cable socket are reversed, so that the positive side of the dc voltage is on pin 4, and input side from the mechanism to the junction box relay is going to pin 3. I placed them in the correct locations, powered up the jukebox, and immediately blew the 8 amp fuse on the ac side.Restored the wires to their as found positions.  Lights work, but rest of the box is dead, save for the turntable which keeps spinning. Doesn't make any sense. any thoughts?

Entire manual with wiring diagrams is here. (Great source for manuals, btw)

http://thearcadeboneyard.com/Jukebox_Manuals/ami/AMI%20G%20(All%20Files%20Combined).pdf

Thanks,

Chris

[BrianB]

Sound like your Slenium Rectifier is good @ 29V. Again, I would check the Credit Unit. Just beacause the solenoid is firing and the credit wheel is rotating doesn't mean the main credit switch is adjusted properly.

The wire going to Pin 4 on the Mechanism Cable Socket should be coming from the Junction Box Relay. The wire going to Pin 3 on the Mechanism Cable Socket should be coming from the 8/10A Mechanism Fuse. Sounds like you got that put back in the right place.

The reason I am focusing on the credit unit is because it is the next logical spot in the cycle of operation. First, Inspect each wiring harness & connector to ensure that there is no visual physical damage. Using the manual, check and make sure that all connections are properly made and seated. Then check fuses. Next check your input/output voltages for a machine at rest. All other voltage can only be read/monitored when the machine is in operation playing a record. Next check and make sure all of your switches are adjusted properly. Too many people mess with switches in attempts to fix/free-play machines and they have no clue what they are doing, only good intentions!

I would then thoroughly read through the cycle of operations and go step by step. I can tell you fro experience, if your Credit Unit isn't electrically & physically working correctly, your electrical selector/keyboard won't work a lick.

Is your green bezeled "Select" light on your mechanism surround indicating that you have credits?

[cdc1960]

Thanks Brian, I appreciate your response. I replaced the selenium rectifier with the silicon bridge rectifier just for peace of mind. The reversal of Number 3 and 4 pins on the Mechanism Cable socket appears to have been right from the factory, but doesn't make sense. I returned them to their as found "incorrect positions", but I will check to see if they have been reversed at the cable end that plugs in to the mechanism at the mechanism  junction box beore changing them back to match the wiring diagram.

The carriage transfer motor runs but smokes, but I have a replacement that I will install after solving the DC power issue. I believe there is a problem somewhere in the DC harness as the credit unit is not powered. Things are acting very intermittently on both the AC and DC sides and I believe it is all associated with crumbling wiring.

I have inspected the AC wiring harness and found that most if not all ac cables are rotten. I have made and installed a new cable from the control to junction box and rewired the top light, which also had flaking insulation. Next is the turntable motor AC cable which was without insullation in five spots. The amp power cord will be next.

My plan is once the AC network is safe, I'll start on the DC side. I appreciate your input and will keep you posted. Thanks again for the help.

Chris

 

[cdc1960]

Brian,

tried it again tonite, checked the wiring to the mechanism junction box up top, and the wires were reversed to compensate for the error in the junction box! hooked up the entire DC side (left the AC stuff that needs rewiring unplugged) and everything functions, with a couple of small exceptions... the credit light won't go out even when the machine is out of credits, assuming it may be the switch in the credit unit that energizes the light, and the contact that starts the record return doesn't work. If I close the selenoid by hand it functions. Also the carriage travel switch that picks up the odd numbered selections doesn't work, but the even number one as the carriage travels from right to left does... sounds like it might be a lot of dirty points... I replaced the carriage transfer motor and it works fine... more tomorrow night...

Chris

[BrianB]

Chris,

Awesome! Sounds like you have made some progress!

When I restored the F-120 I ended up replacing almost all of the wiring in the box. The only wiring I didn't replace was the Keyboard harness wiring and the wiring from the Selector Banks. Typically, all of the black zipcord is suspect and I always check the connectors at the pin level and underneath the aluminum backshell.

[BrianB]

Chris,

Make sure to go through and adjust the Credit Unit as outlined in the service manual. If you follow the steps exactly, I think that you will solve a lot of problems.

I think that you will find that you switches are misaligned. Check switch "CL", it controls the Credit Light. As far as the mechanism function goes. I highly recommend reading through the basic cycle of operation and figure out what it is doing on it's own and what it's not doing. Then check all switches and clean/adjust all contacts.

Let us know what you find out!

[cdc1960]

Brian,

I was concentrating on replacing the AC to the turntable motor which took a couple of hours last night, but I did take a quick look at the credit unit. It appears that the last credit is not being cleared (the wheel won't return completely to the zero position). If you put one credit on the machine the bulb lights, but the selector bank can't release it. There small click is heard when a button is pressed. Add a second credit and the selector bank and the knocker work. The last credit can be released by hand as described in the escapement description, by operating the reset armature with a finger. I'm puzzled about how to correct this, as it is not clearly covered in the credit unit adjustments.

Chris

[Kilroy]

I would also check to make sure it wasn't jury rigged to leave a credit open for free play. It usually  results in bad things, like fires,  destroyed solenoids, etc