Rock-Ola 488 Speed Fluctuation Issue

[Vercus]

Hello,
I'm having a problem with my Rock-Ola 488 keeping steady speed. It has a consistent fluctuation that happens with each rotation of the platter. Does it once per revolution. It's pretty bad, enough to make me sea sick.

I don't know where to begin as I'm not really familiar with idler drive turntables. I've always had either belt drive or direct drive machines.

First off, it does it with every record, so it's not a specific record at fault. The machine was thoroughly disassembled, cleaned and lubricated before I got it. All bearings seem to have plenty of oil.

I'm wondering, is the main platter bearing shot? Where do I begin to check this out?

Thanks in advance,
Jon

 

[Doghouse]

I've a 468 which has the same mechanism.
The turntable spins on a shaft with a point that sits in a socket. effectively there's no bearing it's metal on metal. Just a few drops of oil in this socket is all that's necessary.

Try spinning it by hand to check in the direction it should turn a nd cherck that it turns smoothly.

The drive comes from a rubber wheel kept in position by a spring that rubs on the motor pillar and the inside of the turntable rim.

Remove the turntable and put the machine on "Scan" and check the action of the jockey wheel turning on the motor shaft. That should function smoothly.

There could be a few causes of your problem. grease on the jockey wheel or the underside of the rim of the turntable where the jockey wheel comtacts it.

A worn jockey wheel.

Incorreect tension of the jockey wheel spring.

A "ding," in the side of the turntable that means the rim isn't perfectly "true"

The cartridge cables dragging on the surface of a record.

A faulty motor.

 

[Vercus]

I checked that it's level. Everything spins freely and is clean. Nothing is dragging (wires, etc.). I'm guessing maybe something with the platter itself?

-Jon

 

[ScottSerpa]

If you look at the idler you will probably see a slight dimple where the motor spindle sat for a long period of time. Clean the spindle and inside of the platter and either replace or have the idler rebuilt and you should be good.

 

[Vercus]

ScottSerpa,
Cool, thanks for the suggestion. I'll check it in the morning when it's brighter and get back to you.

-Jon

 

[ScottSerpa]

I've got a guy that rebuilds these idlers for me. Let me know if you want his contact info.

 

[Vercus]

Well I'm about at the end of my rope with this thing. The idler looks fine in the sense that it is perfectly round and not indented. I wonder is it too hard to grab the platter effectively?

It has this consistent fast-slow-fast-slow thing going on, like a boat rolling on the ocean. It's enough to make me seasick. It's definitely getting worse. It's once per revolution, consistently. I can watch the label go around, and see/hear that it's at the same spot every time.

Would you suspect the idler or the platter? I don't know where to begin. I have company coming over in less than three weeks and wanted to have the machine ready to show off.

Two months ago I was confident, but now it's totally gone to crap. How can it get this bad in such a short period of time? Part of me just wants to get rid of it and go back to listening to music on digital streaming services where I'll never have to worry about this crap again. Maybe I need a ROWE CD jukebox instead.

-Jon

 

[ScottSerpa]

You can clean the inside of the platter lip but my money is still on the idler. This is the guy that I use to rebuild them if you want to take a shot: http://terrysrubberrollers.com

 

[gottliebgreg]

I had the same problem with my 425. Changed turntable motors, motor support grommets, idler wheel. nothing helped. Finally changed out the platter and PRESTO, problem went away. Seems either me or a previous owner dropped the platter at one point and dinged it.

 

[Doghouse]

I had the same problem with my 425. Changed turntable motors, motor support grommets, idler wheel. nothing helped. Finally changed out the platter and PRESTO, problem went away. Seems either me or a previous owner dropped the platter at one point and dinged it.

That's my opinion too. I think the jockey wheel turns too fast to cause what has been described as the symptoms.

 

[Vercus]

I was kinda thinking the same thing. Since it's once per revolution I figured it kinda had to be the platter. Now where would be a good place to get another platter for one of these?

-Jon

 

[Doghouse]

I was kinda thinking the same thing. Since it's once per revolution I figured it kinda had to be the platter. Now where would be a good place to get another platter for one of these?

-Jon

There's plenty of them avalable.

If you were in the UK. Then here. But the postage would be quite expensive to the USA.

https://www.jukeboxparts.co.uk/rock-ola/spare-parts/turntables/motors.html

There must be similar supppliers nearer to you.