Phonoland

Hi Guys,

Havent been on here for some time, other projects took all my time!

I'm looking for a replacement turntable motor for my Rockola 442. As far as I can see most Rockola motors from the late 60s to the 80s look the same with the 3 mounting points that hang from grommets.

Are they generally interchangeable? There seem to be many part numbers for motors over the years, are later ones better than earlier models? I guess it depends how well maintained they are and how many records they have played?

Thanks
Adam

Adam,
i do not know for sure, but I think they are all interchangeable. I believe the different numbers indicate different type mounts (studs/screws) and different length lead wires, as well as different type plugs attached to the wires. They also used one motor that had an oil tube for the bottom bearing--this may have accounted for one motor number change ? Some motors also have the dual speed armature.
The "key", IMHO is proper oil--if oiled properly, they will run "forever"--- Ron Rich

Thanks Ron, I always appreciate your input.

I did notice something curious....

My motor has 2 oil filling pipes on it, one for top bearing and one for bottom. My motor hangs off grommets with a washer and c-clip holding it in place.

Looking at my schematic however, the motor is mounted using screws and spacers, along with the grommets, so I guess somebody subbed this out at some point. I wonder if this would cause any problems...

My motor works, but is very noisy, I'd ruled out grommets, I've stripped it down and oiled with 3-in-1 motor oil, but still it makes the tone arm vinbrate. I reached the conclusion after ruling everything else out, that it was either 1) Worn idler bearing 2) Worn motor bearings.

I cant seem to get hold of the idler bearing just now so wanted to trying replacing the motor. In the worst case, if it doesn't resolve it I have a spare to keep or sell on to somebody else.

Most motors I see for sale in fact have NO oil fill pipes on them! I guess somebody removed them when stripping down...

Hi Adam,
On motors of that type, they need to be "re-aligned" if opened. I have never found the exact process for doing such, but have just "snugged" the mounting nuts and tapped gently on the housing till there was no more motor "noise". I THINK, oil tubes were added to the later motors---
As for transmitting noise to the turntable--what colo(u)r are the grommets on your phono ??
Ron Rich

Hi
Operate the motor with the turntable off and the idler wheel removed or pushed out of the way from the motor shaft and see if you het any rumble or noise from the motor, should narrow it down then
clones

Ron, Yeah it took a little of what said you get the motor lined up again, I've had a similar experience with Garrard turntable motors too. The grommets are black ones, though there don't seem to be any others around.

Clones, When I do that, most of the noise is coming when the idler is engaged, so perhaps it is my idler bearing after all. It would be a shame as I can't seem to find this part at any jukebox stockists . I have tried to quieten this down by replacing the fibre washers with home made ones using thin ptfe sheeting, but that only made a marginal improvement. The idler bearing does look scored, probably from years of running with an over tensioned spring on it. I've replaced the idler and the spring with correct parts but I guess the damage is done

Hi Adam,
It has been my experience that ONLY the white grommets work well on RockOla's. I know others say they have had luck with the black ones, but I never could make them work to my satisfaction-- the correct ones are still available from the suppliers listed above, as far as I know--Make sure to install them with the "domes up"-- Ron Rich

Well, I found someone in the UK who has light / white looking grommets, and does claim them to be superior to the black ones.

They should be here any day now, when installed Ill let you know if I found any difference.

I am also sending parts requests in the hope I can replace the idler bearing shaft too. Really want to fix this problem for good. Im not averse to a little bit of rumble, I have plenty of old idler drive decks. But on this juke I need to keep the bass down or it really is quite oppressive.

Hi Adam,
I had another thought--are the transportation screws loosened so that the mechanism shelf "floats" ( on good springs ?)) ?
Many times I have heard motor noise on a machine that was bolted down for shipment ---
Ron Rich

Thanks Ron, that didnt occur to me. From what I recall it is sitting correctly on springs, but I will double check this.

The white grommets arrived, so I will be giving them a go real soon. Just based on feel they do seem different and potentially better at dampening than the black ones, so I'm hopefull!

Hi Ron, changed the grommets, no noticeable difference in rumble unfortunately.

I have the idler bearing on order now and will report back results when I change that part out.

Just a thought--is the correct spring installed ?? Ron Rich

Hi Adam,

The Rock Ola turntable motor is made by the same company that made them for Rowe Ami, it is basically the same motor with the top plate different for the screw down fixing and the motor shaft is not stepped as the Rowe Ami one is.

There should be up and down movement on the motor shaft, but no side to side or front to back movement on the shaft.
If this is the case the motor will need replacing because usually both the bearing and the shaft wear, if you strip the motor down more than likely you will see the wear.

Regards
Alan

Alan Hood
ami-man
UK

To add to Alan's train of thought--
The usual reason the motor is worn is, lack of proper oil, AND, sometimes "someone messing with" the spring tension--
That spring need only have enough tension to hold the idler wheel, LIGHTLY, next to the turntable, and motor shaft when power is removed.
Ron Rich

Thanks guys. There doesn't appear to be any play as you describe in the motor shaft. But while the correct spring is installed now, when I got the machine it had the wrong spring with too high tension on it, this seemed to be a bodge job to compensate for a slippy idler wheel.. Im 90% that the noise is from the idler bearing so will replace that first, and if no improvement will try another motor, after all it cant hurt to have a spare around - im sure I will acquire another Rockola at some point!