Need some leslie 760 advice

[sjoerd1234]

Hello people,

I've just bought a leslie 760. The bass cilinder wasn't rotating so I got it for a for only 120 euro's (150 dollars). The reason it wasn't rotating was because of a metal part in the motor kept getting stuck between the rubber that was rotating so I've fixed that. Making it a great deal for me for only 120 euro's. now I don't really know how a leslie like that is supposed to work. At what kind of speed does the basscilinder normaly rotate? the same as the upper cilinder? Now it is rotating much slower than the upper cilinder. About half as fast. Is that normal? Is it smart to oil anything up? The thing hasn't been opened for 30 years so it is very dusty and used so does some oil do any good? About 30% of the playing the uppertones don't sound like their full capacity. A little soft or cracking sound comes like it wants to squeeze through. Most of the time it does but it returns when I start playing again after I stopped. I had this problem with my Hammond organ also when i first bought it but that disappeared after a couple weeks.

I would much appreciate the help

Greetings from The Netherlands,

Sjoerd

[Wes]

You should disassemble the motors, oil them (Hammond oil works), and adjust them, any time you buy a Leslie.

But what you describe sounds normal to me in terms of motor speed. I can't really comment about the sound.

Wes

[sjoerd1234]

You should disassemble the motors, oil them (Hammond oil works), and adjust them, any time you buy a Leslie.

But what you describe sounds normal to me in terms of motor speed. I can't really comment about the sound.

Wes

About disassembling and adjusting. What would I have to adjust? The speed? I don't really have any knowledge about doing this. I am a little bit good with elektric things though. Any advice as how I would need to do this? If it isn't to much trouble

[Wes]

http://bentonelectronics.com/servici...leslie-motors/

Make SURE you take lots of pictures and notes -- very often the motors' springs and washers and stuff differ from motor-to-motor and do not match the diagram.

Before disassembling, watch what happens when you change speeds.

Here are some pictures I took when doing my upper motors -- http://www.flickr.com/photos/shellya...57628370889289

Feel free to ask lots of questions. Lots of knowledgeable folks here! I'm still quite new at this.

Wes

[jdoc]

main adjustment is spring tension and the angle the motor hits the tire, clean, lub and adjust out of the Leslie in the correct orientation using a (jury)rig will save time as some motors are tough to access...............easy peasy but tedious

[sjoerd1234]

I will definitely try this. Thank you for the advice. I found out that the motor for the bass has a problem. It works fine till a point. When I use the leslie at normal speed everything is ok. When I go to slow speed the little metal rod moves down on the rubber band making it slow down wich is normal. When I go normal speed again the upper motor moves the rod back up away from the rubbermaking the motor go full speed again. When I look at the bassmotor when pushing the fast button I can see It wants to move the rod back up but It cant. It moves the rod back up for about a millimeter and the blocks making the motor stop rotating. Do you think I can solve this by disassembling the motor a oiling it? Seems possible right?

[jdoc]

the shaft angle is adjustable, the spring assists, there should be no contact on slow and good contact on fast

[sjoerd1234]

the shaft angle is adjustable, the spring assists, there should be no contact on slow and good contact on fast

I'm sorry, could you be more specific? Dont you mean that there should be contact with the rubber and rod on slow and none on fast? because that is the situation right now and the upper motor seems to work just fine like this.

[Wes]

Yes, jdoc typed it backwards.

If you study the slow motors carefully, you will see that when they are not turning, their natural rest position -- assisted by either gravity or a spring, depending on orientation -- is to have the armature mostly below the stator. When power is applied to the motor, the stator is energized and the armature spins, moving upward until it is centered in the stator. It can sometimes overshoot the mark on spin-up, which is why an O-ring or fiber washer is on the other side of the armature, to cushion the thump and make sure the armature does not hit the bearing holder.

The shaft that touches the rubber tire is the armature shaft for the slow motor, and must be free to move and down with the force of gravity and the magnetic pull of the stator. The rubber tire is connected to the fast motors, which just passes the rotation of the slow motor on to the rotor when the fast motor is off and the slow motor is on.

As I said, the orientation of the motor affects whether or not the spring pushes the armature out of the way, or helps the stator; same goes for gravity. So it is important to use the right spring -- don't get them mixed up -- and if the spring is not quite strong enough, you can give it a LITTLE stretch. Too much of a stretch and gravity and/or the stator's pull will not be able to overcome the spring force.

The most important job of the spacers is to keep the ends of the spring from damaging the armature and bearing holders. It's important that you have the right sized spacers/washers; if the inside diameter is too big it can get cockeyed and wear a groove in the armature shaft. This grove can, in turn, prevent the armature from reliably sliding through the bearing.

The bearings in these motors are Oilite bearings, which are a porous bronze bushing. The felt in the motors trap oil against the non-working side of the oilite bearing, and oil migrates through the bushing to the wear surface as needed.

Wes

- - - Updated - - -

Oh, and sjoerd, your problem with the lower motor will be improved by lubrication and adjustment - if the angle causes it to push too hard, sometimes the shaft can get stuck. If adjustment and lubrication do not solve your problem, you can try stretching the spring a VERY small amount so that it can push harder and get the armature out of the way.

[jdoc]

sorry, inverted the motor sequence, only for southern hemisphere..........

I'm sorry, could you be more specific? Dont you mean that there should be contact with the rubber and rod on slow and none on fast? because that is the situation right now and the upper motor seems to work just fine like this.

- - - Updated - - -

what he said, no more advice prior to coffee

Yes, jdoc typed it backwards.

If you study the slow motors carefully, you will see that when they are not turning, their natural rest position -- assisted by either gravity or a spring, depending on orientation -- is to have the armature mostly below the stator. When power is applied to the motor, the stator is energized and the armature spins, moving upward until it is centered in the stator. It can sometimes overshoot the mark on spin-up, which is why an O-ring or fiber washer is on the other side of the armature, to cushion the thump and make sure the armature does not hit the bearing holder.

The shaft that touches the rubber tire is the armature shaft for the slow motor, and must be free to move and down with the force of gravity and the magnetic pull of the stator. The rubber tire is connected to the fast motors, which just passes the rotation of the slow motor on to the rotor when the fast motor is off and the slow motor is on.

As I said, the orientation of the motor affects whether or not the spring pushes the armature out of the way, or helps the stator; same goes for gravity. So it is important to use the right spring -- don't get them mixed up -- and if the spring is not quite strong enough, you can give it a LITTLE stretch. Too much of a stretch and gravity and/or the stator's pull will not be able to overcome the spring force.

The most important job of the spacers is to keep the ends of the spring from damaging the armature and bearing holders. It's important that you have the right sized spacers/washers; if the inside diameter is too big it can get cockeyed and wear a groove in the armature shaft. This grove can, in turn, prevent the armature from reliably sliding through the bearing.

The bearings in these motors are Oilite bearings, which are a porous bronze bushing. The felt in the motors trap oil against the non-working side of the oilite bearing, and oil migrates through the bushing to the wear surface as needed.

Wes

- - - Updated - - -

Oh, and sjoerd, your problem with the lower motor will be improved by lubrication and adjustment - if the angle causes it to push too hard, sometimes the shaft can get stuck. If adjustment and lubrication do not solve your problem, you can try stretching the spring a VERY small amount so that it can push harder and get the armature out of the way.