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 Post subject: Rowe AMI JBM Jukebox fix-up.
PostPosted: Jan Mon 08, 2018 12:11 am 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 580
Location: Dallas, TX
No sooner than I finished up work on a Wurlitzer, I was told about a Rowe AMI box that wasn't working. It was working before it was moved to a new owner. Now it simply resets as soon as a selection is made. It hasn't been re-caped or much of anything maintenance-wise done. I didn't find anything loose when I looked it over. I decided to remove everything except the sound system, which I will recap later and the lighting, and bring those items to my place to work on them. I forgot to take any pictures of the out side of the box but this short video shows an identical unit.
https://www.youtube.com/watch?v=JoG4y9W5uok
And here is a video of the mechanism working on a similar unit.
https://www.youtube.com/watch?v=8GCw4hAlU-w
Here are some pictures I took of the mechanism removal.
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DoorOffE1.jpg
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MechanOutE1.jpg
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PartsAtHomeE1.jpg
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Here are views of the mechanism. This one was light enough and small enough to move.
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MechanFronE1.jpg
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MechanLeftE1.jpg
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MechanBackE1.jpg
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MechanRighE1.jpg
MechanRighE1.jpg [ 148.47 KiB | Viewed 151 times ]

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Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


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 Post subject: Re: Rowe AMI JBM Jukebox fix-up.
PostPosted: Jan Fri 12, 2018 4:11 am 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 580
Location: Dallas, TX
I noticed something not right about the phono cartridge. It had been replaced, but if you watched the video of the similar mechanism in action the tonearm is unusual. Instead of the tonearm following the record groove, the tonearm leads the record groove. The cartridge therefore needs to be installed backward from usual. When the cartridge was replaced it was installed the usual way, which is wrong in this case.
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UnderToneE1.jpg
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The side view also shows that the stylus would miss the brush in this position.
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SideToneE1.jpg
SideToneE1.jpg [ 139.68 KiB | Viewed 101 times ]

The end view shows that the cartridge isn't level because a spacer is missing. Luckily I found it in the bottom of the cabinet.
Attachment:
EndToneE1.jpg
EndToneE1.jpg [ 139.32 KiB | Viewed 101 times ]

I removed the search unit and then removed all 200 of the pins and cleaned them. This is after re-assembly. I moved a few of the pins to the selected position.
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SearchUnitE1.jpg
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Another view.
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SearchUnitE2.jpg
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This is a view of the stop switches and reset solenoids where the the search unit attaches.
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StopSwitchsE1.jpg
StopSwitchsE1.jpg [ 143.05 KiB | Viewed 101 times ]

_________________
Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


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 Post subject: Re: Rowe AMI JBM Jukebox fix-up.
PostPosted: Jan Sat 20, 2018 9:11 pm 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 580
Location: Dallas, TX
I make a cart some time ago to hold large projects I would work on. I hadn't used it much, but it was handy for the jukebox mechanism. I used some small scrap boards that I clamped to the cart to hold some of the associated parts like the credit unit and control switch board. This allowed me to power things up and test.
Attachment:
TestCartE1.jpg
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I remounted the cartridge the correct direction for this tonearm.
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ProperCartDirectionE1.jpg
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I discovered what was probably the major problem. A screw had fallen out of one of the relay and allowed the contacts to jam. Luckily I had collected some loose things on the floor of the jukebox and the screw was one of them.
Attachment:
RelayConLooseE1.jpg
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I used some thread locker since there were no lock washers on the screws.
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RelayConFixedE1.jpg
RelayConFixedE1.jpg [ 125.26 KiB | Viewed 32 times ]

I think another problem was that the black wires from the turntable motor were jamming the transfer arm actuating cam. I re-routed them just in case. Maybe the last person to work on it got it wrong.
Attachment:
TTMotorWiresE1.jpg
TTMotorWiresE1.jpg [ 177.43 KiB | Viewed 32 times ]


I found a discrepancy in the manual regarding the wiper timing on the search unit. It was off by two segments causing the wrong record to be selected. This is where it should be with "B1" selected. It is a different circuit board than the one in the manual. Now everything seems to be working fine.
Attachment:
NumWipeTimeE1.jpg
NumWipeTimeE1.jpg [ 143.23 KiB | Viewed 32 times ]

_________________
Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


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