Author Topic: Leslie 147 motor bad noise  (Read 656 times)

Offline guizmo

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Leslie 147 motor bad noise
« on: December 01, 2015, 05:07:17 PM »
Hi everybody,
I post here because I have a little problem with one of my Leslie 147 motor, and maybe someone is able to help me here.

More exactly, it’s the fast section of the motor that rattles when changing from slow to fast. This bad noise don’t appear on each slow-fast transition, but when it comes it’s for approximately 3 sec and it disappears… (listen to my audio sample in attachment, the bad noise appears at 3sec...)

I isolated the slow and fast section and tested them separately to conclude that it’s the fast section that causes the problem.

I dissembled the fast section, cleaned it and oiled it, re-assembled, tested it alone without belt, wheel and it still rattles…

Have you an idea on how to fix my problem?

Thanks, Guillaume

Offline cinnanon

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Re: Leslie 147 motor bad noise
« Reply #1 on: December 01, 2015, 06:43:20 PM »
Sounds like it's mechanical noise to me. First thing i'd do is replace the bearing assembly.
http://www.tonewheelgeneral.com/build_page.php?category=Leslie+Speaker+Parts&subcat=Drive+Train

"TWG Leslie Bearing Set"

Or, remove the original bearings and match them up with replacements. If/when you take it apart, check for drag or play in the bearings. They should be smooth as silk.

Is it on the lower rotor only?
Something tells me it is, because (I think) I can hear the upper rotor spooling up very quickly, and the lower, slower, rotor takes a few more moments to get up to speed, leading me to think it's the lower rotor bearings (looks like 2 total).
« Last Edit: December 01, 2015, 06:51:02 PM by cinnamon »

Offline guizmo

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Re: Leslie 147 motor bad noise
« Reply #2 on: December 02, 2015, 03:04:42 AM »
Thank you for your answer.

You're right when you say that you ear the treble horn rotating. And yes, the bottom rotor has a slower acceleration than the upper due to its size and weight (like explained in the Leslie manual, it should take between 5 to 8 seconds to rise, mine takes 6 so it's normal).

The bearings are in perfect condition, and I isolated the slow and fast sections of the bottom motor and this sound comes from the fast section. I tested it outside of the cabinet in my hand, without the slow section, without the belt, so without any bearing engaged.

Exactly like in the attachment picture configuration, nothing else.

Thanks, G

Offline Electrickey

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Re: Leslie 147 motor bad noise
« Reply #3 on: February 02, 2018, 05:24:46 AM »
If the motor makes a noise when isolated it needs to be disassembled and overhauled or just get another motor.

There are YouTube clips showing how to take apart this Leslie motor.

Or you can send it off to someone who can rebuild it for you like Rick at TWG if you'd rather not work on it yourself.


Offline 4kinga

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Re: Leslie 147 motor bad noise
« Reply #4 on: February 02, 2018, 07:10:43 AM »
It could also just be a slow motor adjustment or a bad/worn o-ring.  Either way, take the back off and watch the upper stack when switching.

Offline Electrickey

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Re: Leslie 147 motor bad noise
« Reply #5 on: February 02, 2018, 07:39:44 AM »
I know this is a dated post but for posterity's sake, since the OP stated the noise is still there with the motor isolated, it would be easier to just get another motor off of eBay. They are basically the same unit no matter the Leslie model unless it's the newer models without the motor stack. Or take the motor to a motor repair shop. They should know what is going on with a simple motor with an armature.


Offline guizmo

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Re: Leslie 147 motor bad noise
« Reply #6 on: February 06, 2018, 04:59:39 PM »
The motor is still a noisy, but when the cab is closed it’s impossible to ear.
I totally disassembled it 2 years ago, cleaned it, lubed it, changed the springs... nothing to do...
I’m more ok with that noise now^^ When I bought it, I wanted to make the perfect Leslie, it’s not perfect but very good, the wood is shiny, all is clean, it sounds great... my lovely 147 !!^^