ROCKOLA 488 Select Wrong Track/Display Wrong Number

[mikerockola]

Hello All,

So glad to have found a new site like this as the old one from a few years ago disappeared. Also extremely happy to see familiar names like "Ron Rich" around.

Lets get straight to it. I have a Rockola 488 worked perfectly when acquired, I did some basic maintenance like oiling, greasing, swapped the needle, pulled a bunch of parts for oiling. Replaced the grommets. Sent the amp out for a complete rebuild as well as had an AUX cable added. Also moved twice, once across country.

After all of that the 488 *SOMETIMES* picks up the wrong disc and always displays the wrong track number in the little digital display.

Quick example: enter 145, arm picks up 155, display reads 155....or at times enter 145, arm picks up RANDOM track and display reads 155.

Display always reads the next disc up from the actual input, but the wheel reader sometimes just does its own thing.

Any help is appreciated as my kids, wife, and all house guests really enjoy this machine!

Thanks in advance,

Mike

[Ron Rich]

Hi Mike,
Hopefully someone who knows will chime in here--as I am just guessing ! I would start by cleaning the opto that counts the record spaces and what ever stops the mechanism at a selection -- on the older RockOla's that was a relay-- if still the same on a 488, check the contacts for proper gaping and /or, "pits"-- Check for "slop" between the basket motor and the drive gears ?? Ron Rich

[jukenorman]

Hi Mike, the first thing I would look at is the plastic flange on the encoder disc for the opto that counts the record spaces. I think every one I have ever seen is badly cracked and very loose. I normally put a large thick cable tie around it and then ensure that there is no "play". Then you can carry out the calibration, details of which you will find in the service manual.
Norman.

[mikerockola]

Thank you both for your replies, gonna get in there and check out that little plastic flange and try the zip tie if I find it to be cracked. Would this also effect the wrong number to display in the digital display above the buttons?

Thanks guys!

[jukenorman]

Hi Mike,
I agree that is a bit odd (although I could come up with a scenario where that would happen), but it's fairly straightforward to check for play in the opto encoder disc so I would start there so that we know that bit is good!
Norman.

[mikerockola]

Thanks guys,

So I did not find any cracks on the plastic ring/flange around the opto. Is it possible the opto is faulty?

It passes most of the opto test but not all, on some of the tracks it picks up the wrong number. Also if you enter 2-3 songs it will sometimes pick up the right songs but in the wrong order, and the display never says the right track if you select 126 display reads 136 or 146.

Do I need to replace the Opto board or is there another option?

Thanks all!
Mike

[jukenorman]

Hi Mike,
The next thing to check would be that the opto is clean, if you haven't already done that? Also, if my memory serves me, there is an LED that flashes as the carriage rotates - watch it to see if it's missing pulses.
Norman.