After years of spinning and singing beautiful music to you, one day you may just find your faithful turntable looks tired and in need of repair, i.e. the motor speed is inconsistent, as if it's turning slower and slower.

How to check where the problem lies?

Try these few simple steps first:

1. Check if the ball bearing in the main bearing housing is missing (use a piece of magnet or a straw of diameter ~4.5mm). You may use a steel ball bearing of diameter 4.762mm or (3/16") if required.

2. Add one or two drops of suitable lubricating oil (e.g. hypoid gear oil grade 80W90 or light motor oil grade SAE20 or 30) into the main bearing.

3. Put two or three drops of the same oil onto the sub-platter spindle and insert it back into the bearing housing. Let it go down slowly until touching the ball bearing.

4. Make sure that the sub-platter surface is clean- free from dirt or oil.

5. Check if the belt is stretched. Over-stretched belt should be replaced as belt slippage will cause poor energy transfer for turning the sub-platter/platter assembly efficiently. Speed stability would be greatly affected.

6. Check if the pulley is tight on the spindle. Pulley plays a very important role in transferring energy to turn the sub-platter/platter assembly. Inefficient energy transfer by a "poor" (in quality or not tightly fitted) pulley would result in speed instability, hence pitch instability. A very loose pulley can even ride higher up the spindle as the motor spins and rubs against the platter or it's so loose that the motor can't even drive it to move the platter.




In fact most of the plastic pulleys tend to get loose on the spindle due to deterioration of super-glue over time. Try to pull and see if it comes off. If it's so, you may glue it back using super-glue or you could take this opportunity to treat yourself to a stainless steel pulley upgrade for better energy transfer which brings about significant sonic improvement.


Hope your motor speed problem is solved at this point and you won't have to read on!


But for Rega Planar 2 or 3 turntables, you may encounter additional problems after fixing the new belt i.e not only the motor speed problem is not completely solved, you feel as though:


...The motor is kicking the platter
...The motor is rubbing the plinth
...There is sound of friction

Why it happens after changing to a new belt, you may ask....


Let's look at the Rega Planar 2 or 3 suspended motor mounting:


The motor is held by using rubber suspension band to the aluminium mounting plate which is screwed onto the plinth.

As time goes by, the rubber suspension band loses its elasticity. The motor not only wobbles more, it also tends to slant towards one side. After fixing the new belt, we find the motor/pulley experiences a bigger tension resulting it to knock/rub against the plinth.

To confirm this point, run the motor without the belt on for a while to see if the sound of friction exists. Then put the belt back again and run the motor to compare the result.

There are a few ways to solve this Rega motor rubber suspension band problem:

1. Change the rubber suspension band, but the motor would still wobble causing speed variations, hence pitch instability.

2. Discard the rubber suspension band and use double-sided tape to mount the motor to the plinth instead, à la P3-24. This will solve the wobbling problem but the motor vibration would be transmitted to the plinth, whence to the record and stylus.

3. Go for Rega motor upgrade on sticky pad (110V or 24V), but it's costly (moreover, motor is not the cause). Besides, the problem of motor vibration to the plinth will not be completely eliminated, though you get some improvement due to lower vibration motor with aluminium pulley.

4. Resolve to motor isolation base tweak which isolates motor completely from plinth. I have done that for my own Planar 2 and 3.



When Jani of Finland communicated with me because of this problem, I suggested he use the motor isolation base. Motor upgrade was not really necessary in my opinion.

And here's Jani's reply after mounting his motor to the motor isolation base :


I decided to do it your way instead of upgrading the motor. Why fix something that is not broken? The broken part would be the rubber suspension for the motor, which was probably tired and did not allow for the replacement of a new Rega silicone belt. The new belt drew the pulley out of alignment which resulted in an annoying click when the silicone belt wobbled.

Not so anymore!



Read more on ...... Jani's joyful experience!





5 comments:

Charles Erb said...

Thanks for posting these ideas. I bought my Planar 3 back in 1990, but hadn't used it for about 5 years. Your advice has got it back on form again.

There's still a special pleasure in listening to LPs, despite the occasional pop...

Domini Taylor said...

Thanks so much for this advice - couldn't find it anywhere else. Reall useful site this.

Driveparts Direct said...
This comment has been removed by a blog administrator.
Unknown said...

Thanks a lot for the tricks! I've just bought a "slow" planar 3 and applied all your suggestions; now it works fine, but I still have a doubt... maybe you can help me. The motor shaft (not the pulley) is not completely fixed: it moves 1 or 2 millimetrs up and down. Do you think is it ok?

Michael Lim said...

Hi

The motor shaft should have some play otherwise it can't turn. You should get the height adjustable type so that you can adjust the thrust bearing for optimal motor performance.

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