Juke Displays Wrong Selection + Picks Up Wrong Disc On Certain Numbers.

Hello all,

This forum has been extremely helpful and I wanted to say thank you to everyone's input. With that said, I recently completed a complete refurbishment of my Rockola 488, I sent the lid frame out to be rechromed, had the amp rebuilt, reconed some speakers, re-insulated the entire cabinet as the old stuff had basically turned into dust, I also oiled/greased all of the moving parts and the motors, also had an input cable installed on the amp for iPhone/iPod hook up.....Juke sounds and looks better than I have ever seen/heard it.

But now the display shows a selection number that is ten digits off the real selection.....if I select 110 it may play 110 but it displays 120....also on certain digits (so far ones that end in 50) it actually picks up a selection ten digits ahead or behind the entered selection.....I did not mess with anything other than the above mentioned parts....and I am still a total newb but I am pleased with the end result other than this current issue.

Does anyone know what I can do to fix the display selection or the pick up of the wrong selection? I read the manual and did multiple tests it says to do but have not yet been able to resolve the issue... Any help or advice is appreciated!

Thanks to all!
-Mike

Also replaced lamp starters and one bulb that had never lit....the machine looks impressive now.....80's impressive anyway!

Hi
Check the 9.6 volts on the power supply from pink wire to ground, if its out it can cause strange things to happen with the later rockolas, it can be adjusted with the trim pot, its detailed in the manual. If that doesn't help it could be the opto assembly beside the record basket which keeps count of the record slots, the solder joints on this are know to give trouble. If not any of these may be a problem with the logic board and/or profit setter
clones

Clones,

Thanks for your reply. Over the weekend when I have time I will check out the areas you mentioned. Hopefully it is one of the two, and a simple fix! I did have to disconnect the ground wire when I took apart the lid frame to get it rechromed so I'll start there.

I'll let you know how it goes. Thanks again.

Okay,

I went ahead and ran through some of the tests in the service manual, and when performing the test procedure for the Logic Board the only 100/200 were picked up (and the display read 110/210) and for the other selections the wrong records were picked up each time.

I wanted some input before I go tinkering with the Trim Pot and the Opto Board....does this seem like a dead Logic Board that needs to be replaced or would adjusting the Trim Pot and/or the Opto possibly correct the selections/number displayed. I ask because the way I read it in the manual it seems like the Trim Pot is really for the alignment of getting the record in and out of their spot (or making sure they are dropped with enough space) as opposed to selecting the wrong records/displaying the wrong records, but I am a total amateur and thus I am open to any input.

This is actually starting to get fun now that I have found my way around the machine quite a bit....just sad that repairing it led to an issue that was nonexistent 'pre' repair. hmmm. Thanks.
Mike

Hi
The pot I was referring to is on the pcb attached to the front of the power supply and used for adjusting the 9.6volts not the one on the logic board. If the 9.6 volts is out it can cause strange things to happen to the machine. The opto board beside the record basket counts the record spaces, see if it flashes when the basket scans for each space. If there are erratic selections it may be related to faulty ic's on the logic board
clones

Clones,

Thanks for getting back. Is it safe to say its the ICs in the Logic Board if the 9.6v LED is lit on the board of the Power Supply, and the LED on the Opto lights as I use the scan switch to scan through the basket....Opto LED lights at every selection and turns off at the big gap between the end and the beginning and starts again. Or even with the 9.6v LED lit it could need pot adjustment? (I located the pot you are speaking of).

Seems like I may need to send my board out for repair or buy a new one. Only place I found that offers such a service was one in the UK.\

Thanks.

FYI--("almost") ANYTIME you have either a lamp, or a LED showing "voltage"--it never indicates that the voltage is correct--it only indicates that "voltage is present" . In this case, you need to measure it with a very accurate meter, and adjust it as necessary. Ron Rich

Ron,

Thanks for the input. I'm going to head off to HomeDepot to pick up a multimeter. Any pointers on from where to where I will be measuring the voltage? I scan the manual as well once I am home to see if I can find that answer.

Thanks.

Sorry, I don;'t remember where that test point is--I know I have found it before--but that was at least 25, + years ago-- Ron Rich

Hi
Measure from pink wire at power supply with + end and - probe to the chassis of the machine
clones

Ron and Clones,

Thanks for all of the helpful information, it's like I have a tech here telling me what to do step by step. I really appreciate it. With that said, I hooked up the multimeter (on DCv) to the pink wire at low voltage and to a ground....the voltage read below 9 at around 6. I adjusted it to 9.68 the closest I could get to simply 9.6.....but no dice the juke still makes random selections instead of those put in via the keyboard and even when it makes the right ones for instance '100' it will display '110'. What's my next step? Does this mean the logic board is done?

Thanks,
Mike

Hi Mike,
Sorry, I don't know that RockOla system at all--I never needed to as there was a great guy, who went by the name of "RockOla Charlie"--He knew it all, and always got me out of any jam I got into on them.
Do you have the Service Manual package for that model ? If not, IMHO it is an absolute necessity. They can be purchased at a supplier listed, above, in the announcements/sticky section of this forum.
All I can offer is a non-educated guess--Is/are there (a) any batteries in that model ? If so, I would check them, turn power off, remove them, turn power back on, and see if that corrected the problem. If so, and the batts are a "snap in" type, install new batteries, with the power ON. If it/they are the solder in type, you need to change them with the power off-- Ron Rich