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Post by mauro on Jul 21, 2018 1:56:46 GMT
Greetings again!
Having completed my Wurlitzer repair I thought I'd give this AMI a go as I have been bored in the evenings lately.
I'm pretty good with late 50's AMI's but this model 800 record changer is completely foreign to me.
The problem is when I plug it in the turntable just starts spinning with the bow still over the record magazine and I can't get it out of this mode.
I think the problem is getting the relay in the junction box to energize as it is not.
My manual states this relay, when energized, removes power to the turntable and transfers power to the carriage motor.
If anyone is familiar with this machine perhaps you can point me in the right direction?
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Post by Ron Rich on Jul 21, 2018 2:58:52 GMT
Mauro,
Schematic time-- fuses on the DC supply ( either 8/10 or 1 amp ) good ?? 30vdc good ?
Ron Rich
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Post by robnyc on Jul 21, 2018 3:58:33 GMT
Mauro, I have only the "F" phono book but there were few changes on AMI's back then. Take a look at the cam shaft switches: www.flickr.com/photos/90641375@N06/41485970272/ -these determine what-happens-when on the changer itself. That era of AMI machine almost always has deteriorated cabling so -proceed with caution- and plan on wholesale replacement of the harnesses. It is best to unplug the turntable motor as it has full line current till new wire is installed. RobNYC |
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Post by mauro on Jul 21, 2018 12:36:03 GMT
Ron, fuses are all good and all voltages present. I previously changed the selenium rectifier to a silicon bridge during my unsuccessful initial attempt at this juke a year ago.
Rob, all wiring has been replaced.
I will have a closer look at those cam switches today.
Thanks guys.
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Post by Ron Rich on Jul 21, 2018 13:25:41 GMT
Mauro,
If the gripper motor voltage is good, I'm seeming to re-call that the ice cube relay is in that circuit ?
Ron Rich
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Post by mauro on Jul 21, 2018 14:54:35 GMT
Ron,
Lots of relays on this juke but I don't think any of them are the covered cube type.
This morning I removed the transfer motor and turned the cams by hand until it loaded a record on the turntable hoping that in this position the cancel switch might work but no luck, now I have a record spinning on the turntable.
I've tried to activate every relay by pushing them with my fingers but nothing changes.
Cam switches seem to be operating normally and were clean as I did the cleaning before putting it aside last year.
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Post by Ron Rich on Jul 21, 2018 21:18:10 GMT
Gonna need to "get out the book"--and read it-- If you have not done so, I would suggest that you check all switches, and relays on the mech with a good analog meter, to be sure they can carry the prpper current-- Ron Rich
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Post by mauro on Jul 21, 2018 22:26:15 GMT
I have read the manual cover to cover.
The thing they missed is they tell you what all gaps and pressures should be for the contacts but they don't tell you what the contact actually does.
You can get that from the operation explanation but it's difficult to cross reference the schem-a-grams at the same time.
I've actually got the mech to move now but turntable always turns, can't figure out how to get it to end the cycle.
Also the end fuse 8/10 amp keeps blowing, most likely because it's trying to run everything at once.
A strange thing, when the fuse holds, the cancel button makes the mech scan?
I'll just keep trying to decipher the manual.
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Post by robnyc on Jul 21, 2018 23:22:18 GMT
Mauro, on those old AMI modeal the T-T motor is controlled by a relay connected to the cathode ckt of the amp output tubes. The idea, as you may already know is to wait till the tubes have output before turning on the motor.
The amp is in-turn connected to an outlet somewhere on the junction box (IRRC). So if the mech is not scanning or playing a record, the amp tubes should be dark.
Apologies if you've already gone over this stuff.
Rob
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Post by Ron Rich on Jul 22, 2018 2:32:30 GMT
Mauro,
The cancel button on the mech serves as a scan button if the service switch is in the service position, at least on later
Rowes--don't recall when they started that ?? Ron Rich
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Post by mauro on Jul 23, 2018 1:51:35 GMT
Ron, you ate correct about the cancel switch operating as a scan switch when the DC switch is turned on.
I didn't think they did this until some point after Rowe took over but, like I said, this jukebox is completely foreign to me.
Rob, I did read that in the manual but your reminder helped as at first the tubes were staying lit.
I've made some headway this weekend and my questions will be much more specific now.
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Post by mauro on Jul 23, 2018 2:01:12 GMT
I have the mech scanning now, it was a broken pin in the small mechanism junction box, luckily I had a spare.
The problem now is with the mech detecting in the proper position and the cancel solenoids failing to fire.
Seems that now matter how closely I adjust the stopping switches to activate the mech travels about 3/16" too far and jams against the selector pin. That's what is blowing the fuse.
The reset solenoid does not fire and even if it did, it would miss the selection pin.
I'm slowly working through the schematic but am at impasse once again.
Not sure if anyone can make a remote observation but as they say, "there are no stupid question."
Thanks,
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Post by Ron Rich on Jul 23, 2018 2:34:24 GMT
Mauro,
Didja check the stopping switch(s) itself -- If a "Micro Switch", they are famous for not being exact at making contact at the same time, when "old"-- Ron Rich
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Post by mauro on Jul 23, 2018 11:47:50 GMT
Micro switches checked good with my analogue meter. I checked them multiple times to make sure they are not intermittent as well.
Will play with it again later today and see if it will offer up any clues.
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Post by mauro on Jul 24, 2018 0:13:11 GMT
More specifically now,
Carriage switch makes and DC should be redirected to Selection relay and to gripper motor and this should cause dynamic braking of the carriage motor but none of these things happen.
All relays have the proper resistance and all associated switches show good contact.
I'm trying to follow the voltage now but not having any luck yet. I'm wondering if someone previously moved wires around, but thats unlikely.
I'll keep chasing the voltage path and checking in to see if there are any more suggestions.
Thanks.
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