Rockola 474 trips breaker

[starjerseys]

Hello Everyone!

1st post. I restored this Jukebox for someone about 2 years ago, now he's having the following problem. The record is placed on the turntable, the tonearm moves to the correct position & starts playing, after about 3 seconds it trips the selection breaker. After studying the circuit diagram, it looks like one of the micro switches could be bad or the cam shaft is out of adjustment, am I on the right path? I would appreciate any help on this. It's about 1.5 hours away, so I don't want to make multiple trips. I tried to attach a video he sent me, but it won't go thru. Thanks!

Norman

[jukenorman]

Hi Norman,
Quite difficult to say exactly what might be wrong but when the music cycle starts micro switch 3 changes over. You would think that it's unlikely to be a micro switch short because you would expect the CB to trip immediately. More likely to be a problem on the interlock release relay coil or maybe, if you're lucky, the 47 ohm resistor in series with it?
(Another) Norman.

[Ron Rich]

Hi Normans---
For this discussion, I'll number you Normans, # 1, and #2. by the order of your posts here --
Norman #1. Please read your messages.
Norman, #1 , & #2, I would ASSume that if the music starts, the CB trips because the gripper motor is still attempting to turn, but since it's in the end position it can't. Once again, an ASSumption-- the Micro Switch has not released the relay, or the relay is locking up, for other unknown reasons. Ron Rich

[doghouseriley]

I don't know if this helps, but I had a similar problem with my 468.
It could trip out without warning, usually after pressing the scanning lever or during scanning, or after selecting the first record, while the carousel was turning, or sometimes as the record started to play. If I preseed the mech reset it'd then behave itself.
I posted about it here. It's still behaving.


jukeboxaddicts.proboards.com/thread/2085/quite-simple?page=1&scrollTo=12270

[starjerseys]

Hey Guys, thanks for the replies. I forgot to mention, I checked out this problem in person 2 weeks ago, there's a large micro switch under the scan switch, if I held it in (closed), the record would keep playing. Does this help any?

Norman

[Ron Rich]

H Norman,
A "Large Micro Switch" ? Ain't that oneov them thar oxy-morans ?--say like "Jumbo Shrimp" ?? What operates that large switch ?
Ron Rich

[jukenorman]

Hi Ron,
Yes probably you are correct that the gripper motor is still attempting to operate. Possibly micro switch 3 is not fully changing over ie it's opening to de-energise the mute relay but the NC contact is not making to operate the interlock release relay - which brakes the gripper motor. I'm not sure about the large micro switch, the A-B snap switch maybe?
Norman1.

[starjerseys]

Hi guys,
The large switch I'm referring to is probably the snap switch, if I push it with my finger the record will play normally with sound. I'm heading that way shortly, I'll let you know what I find. Thanks.

[starjerseys]

Below is a link to the video the owner sent me. When I was there I could get the record to return to the magazine by moving the tonearm to the end of the record & then push the snap switch. Then once a record is selected it would lay down & play for a few seconds & trip the breaker again.

youtu.be/CZNLStL56qw

[Ron Rich]

Hi Norman,
First, and foremost--tell the "owner" not to keep pushing on those CB's-- They do, and WILL go bad ! I can not re-call what activates the A/B snap switch, but it would seem to me that's un-important as that only determines the record SIDE, played ? -- Yes-- I now recall-- it's activated by the cam follower that rides inside the round cam on the basket-- I have seen that dry off and refuse to switch sides--sometimes causing a jam large enough to stop the basket from turning-- but as to causing the problem you have -- I dono ?? Ron Rich

[starjerseys]

Hi Ron,

I will. I didn't have any luck fixing it today. Understanding the wiring schematic is gonna take some time, I can read pinball schematics, but this thing is complicated! I'm not sure where the interlock release relay is nor the 47 ohm resistor. The micro switches did test good. He's going to deliver it to my house so I can troubleshoot it here. Thanks!

Norman

[Ron Rich]

Hi Norman,
Those items are housed in a box, under the mechanism base-- bunch of plugs going to it-- be SURE, all female jacks are good, and plugs are all the way seated. Be sure the phono is properly "tied down" for shipment (see our FAQ's) ! Ron Rich

[starjerseys]

Hi Ron,

That explains that. Thank you for your time! I'll post an update when I have one. Take care.

[Ron Rich]

Hi Norman,
Just remembered-- that control box on most models had a "pull off" cover, and is held in place under the shelf, with two Phillips screws. Ron Rich

[starjerseys]

Thanks Ron!