Rockola 474 (1978) Lock Bar solenoid issue

Hi, new to the forum, and new to jukebox repair.

As a bit of history on my juke (Rockola 474 circa 1978), my wife grew up in a Chinese restaurant as a child, and the coin-op vendor that operated the juke box in their restaurant gave it to them when they retired, after it had been operating for over 20 years. It stayed with her brother for another 15 years, but the last ten it has been in an exterior, unheated garage in North Bay. Since he wasn't using it, he offered it to us and we picked it up about a month ago. It is actually in good shape, as it had one owner and operator for it's life, but was in desperate need of maintenance when I picked it up. All the lubrication had gummed up pretty hard.

I have disassembled most of the mechanical, cleaned and lubricated it. I cleaned most of the electrical contacts that were obvious and accessible. I now have it mostly working, but am having a problem with the selection system. When you put credits in, and push a button, the "1st Selection" light activates correctly. Then when you push a second button, the "2nd Selection" light activates correctly. At this point, the manual says that the Lock Bar solenoid should activate and hold down the lock bar, until the third button is pressed. That doesn't happen though.

If I manually depress the lock bar, the solenoid kicks in and holds it down. I can then make the third button selection and everything works properly from there. The solenoid seems to be working fine, since it will hold the lock bar in place once I push it, but it won't lock it down on it's own.

The manual isn't really helping me at this point, I am just not sure on how I can trouble shoot from here. Any suggestions or tips on what I should be checking or next steps that I could take would be greatly appreciated.

Thanks in advance!

Sounds like a set of switch contacts that initiate the solenoid aren't "clean", yet do finally close when manually pressing the bar.
Dig deeper and find those contacts/switch that obviously is triggered by the bar.
The 2nd selection button activation might have the clue.

Going from my great--but not too long memory, which is never rong, but not always rite, either---
It seems to me the book is either in error, or you have miss-read it. My recollection is that they energize the solenoid as the third number is pushed. If that's true, I would look for something that moves a switch as a number is pushed. It would be my guess ( see the schematic) that this switch would energize the solenoid or a "write-in relay", which in turn would lock the solenoid down until such time as the selection had been made---Ron Rich

On the underside of the keyboard take a close look at the set of open contacts on the right side. These are shown on page 27 of the manual as item 1 at the top of the page. It is quite common for one of these to break off and gives the symtom you describe. Ray

Hi Everyone, thanks for the suggestions.

I ended up completely removing the lock bar mechanism, cleaned and lubricated it. I also took a second shot at cleaning the various switch contacts just in case. Once I put it back together, everything now seems to be working!

Now I just have to rebuild the amp...

My question is--was my memory correct, or not--when does the solenoid energize --at the 2nd number pushed, or the start of the 3rd number ??
Ron Rich

The Solenoid energizes after the second button is pushed.