Rockola 470 trips breaker

[computronic2040]

Greetings, 

I have a 470 that started cutting out after the record started playing. Basically, it dies after starting sequence 19 (tried to link an image, but it looks like that functionality is disabled). I press the relay on the power supply unit and the turntable will momentarily spin. 


Soo I have tried the following:

- cleaned the contacts on the relay in the control box. No luck, switched control box (and cleaned contacts) with another known good one. No luck
- cleaned the microswitches that ride on the cam, checked these for continuity
- switched out the whole power supply unit. swapped relays.

I am kind of at at loss. Please help.

[Ron Rich]

Greetings, backatcha !
Please read our FAQ's section-Hi Newbies post" and how to post a photo -- it can be done !
I don't quite understand what's happening here-- how do you get the record to return to the basket ?
Ron Rich

[computronic2040]

Hello, quick update. I did try to clean the contacts on the trip & release coils. I manually returned the record to the basket and rotated the basket back to the starting position. One strange thing - the basket started to rotate but not stop when the switch was in the operate position. I then manually moved a selector lever - to my surprise the record was selected and played without tripping the breaker, however, when the other side of the record was played, it tripped the breaker.

The only guidance I could find was from an old response by Charlie Maier on the jukebox listserv (below). I kind of get the gist of what he is suggesting - that the hammer coils and micro switches fail? For the control box, where would one check for bad connections?

"Questions first? I assume it's the mech breaker tripping, there are
three breakers. Does it fail on both top and bottom record sides? If
only one, Thonas is correct, likely the coil itself. With a meter they
should read between 25-35 ohms. An easy test is to stop the mech while
the record is transfering, slip a dolar bill between the wipers and the
rings. Turn the mech back on. If the breaker doesn't trip, you have a
bad coil. Number one reason for coil going bad is a bad #3 micro
switch. Change it!. Could also be a bad contact in the control box, but
rare, or wiring problem.
The timing described is a little confusing. The coil is energizes by
the #2 micro and released by the #3.
The #2 is activated as the tone arm travels to the record, which is
after the gripper transfers the record to the turntable. Might also
have a bad #2 micro. Check alignment and operation of switches, but #3
is def bad.
If coils check good, consider a tightness in the gripper mech tha'ts
slowing it down enough to trip the breaker.
Charlie Maier"

[jukenorman]

If the carousel is not stopping in the home position, that might suggest the wobble plate switch is not functioning? You seem to have checked the control box contacts referred to, ie the trip and release relays. Have you metered the hammer reset coils?

Norman.

[computronic2040]

Hi Norman, thank you. You were spot on. A coil on the read out carriage was dead as a doornail (1 ohm). Replaced it, now the selection plays with no breaker tripping. Now to check the wobble plate switch.

[Ron Rich]

Iffin, that coil read "1 ohm", it was not dead as a door nail ! It was "a dead short", which accounts for the breaker popping ! Ron Rich

[computronic2040]

Thank you Ron. Still trying to track down why the readout carriage scans continuously for an A side, but will select a B side no problem.

[Ron Rich]

Should not be much of a search-- somewhere between the AB switch and the contact block that rides the read-out arm ? Did you READ the "common 400 problems" sticky ? Ron Rich

[computronic2040]

Thanks Ron - let the burnishing begin.

[Ron Rich]

Coodbe ? didja read the contact cleaning  & over-center switch, stickies  ?? Ron Rich