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Annoying Noises Coming From My Leslie 251


Polkahero

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Up to now I thought the hum coming from my 251 was due to old caps in the power amp. Well, yesterday I took off the back panels and noticed the hum (around 60 Hz) coming from the lower rotor motor stack. Sure enough, the hum of the motor is being transferred to the cabinet through the bottom bracket. I've attached a picture with the offending gasket circled in red. If I raise the motor stack slightly, the hum disappears! Do you guys think I just need to replace the rubber gasket between the bracket and the wood shelf? If so, who stocks these?

 

Also, the slow motor (top one) on the same stack makes a "crackling" noise when in chorale mode. When I switch to tremolo, the crackling disappears. I think the noise is coming from the spinning wheel part in the aperture, you can't see it from the picture. Does this just need oiling or is something else going on?

 

Other than these minor issues, this '64 Leslie runs like a champ!

http://i967.photobucket.com/albums/ae157/Polkahero/LeslieMotor.jpg

 

 

 

 

 

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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The bracket is mounted to the cabinet via screws inserted through grommets. When grommets age, they harden and thus become less effective at absorbing vibrations. Replace the grommets. Remove them and take one to a good hardware store (not Home Depot but a mom & pop place) and they should have the same size.

 

Might want to replace the ones in the bottom rotor drum while you're at it.

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Thanks for the info, guys. Any comments on the crackling noise coming from the slow motor?

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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I think it's coming from the wheel that spins around in the aperture part of the motor. In tremolo mode this "wheel" stops spinning. Wish I knew my Leslie terms better! Once I get the motor out to gain access to the grommets I can take a picture.

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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I'd replace the O-ring on the back of the fast motor that the slow motor engages for the crackling issue. Also the fast motor is somewhat undersized for the job, it looks like a thin one from a motor stack from an internal Leslie module. The stock fast motor would be much thicker, the laminations would be around an inch and a half thick. I've used the thinner fast motors on horns with no issues. Looks like a motor stack from an internal Leslie module was used as a quickie replacement at some point in this Leslie's life, just at a guess.

 

TP

---

Todd A. Phipps

"...no, I'm not a Hammondoholic...I can stop anytime..."

http://www.facebook.com/b3nut ** http://www.blueolives.com

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I'd replace the O-ring on the back of the fast motor that the slow motor engages for the crackling issue. Also the fast motor is somewhat undersized for the job, it looks like a thin one from a motor stack from an internal Leslie module. The stock fast motor would be much thicker, the laminations would be around an inch and a half thick. I've used the thinner fast motors on horns with no issues. Looks like a motor stack from an internal Leslie module was used as a quickie replacement at some point in this Leslie's life, just at a guess.

 

TP

 

Wow, you have a great eye! I measured both the upper and lower fast motors and you're right: the upper rotor's is exactly 1.5" thick and the lower is 1" thick. Do you think it would be worth it to switch these around? Lower rotor seems to spin just fine right now, my mantra has always been if it ain't broke don't fix it!

 

I've come up with a free fix to the hum issue. I had a 1" rubber disc in my toolbox and placed that under the mounting bracket where it meets the wooden shelf. Hum is totally gone!

 

About the ongoing crackling issue: I don't think it's due to the o-ring being worn. I've attached a picture of the slow motor with what I believe is the offending component circled again in red. Whenever this "wheel" is spinning in chorale mode, it causes the crackling. I've run the slow motor detached from the fast motor and it still makes the noise, so it's not the o-ring causing any issues. I had taken this apart last fall for oiling, do I need to do that again?

http://i967.photobucket.com/albums/ae157/Polkahero/Leslie251SlowMotor.jpg

 

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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That is the slow motor - it has a spring built in to it that raises the shaft when the motor is not powered - so that the shaft does not touch the O ring and drag down the fast operation. If that spring gets gunked up, I have seen the shaft on the slow motor not go all the way down once the motor is powered (the rotor in the motor gets pulled down when powered up by the magnetic force). That has been known to cause noises of various types.

Howard Grand|Hamm SK1-73|Kurz PC2|PC2X|PC3|PC3X|PC361; QSC K10's

HP DAW|Epi Les Paul & LP 5-str bass|iPad mini2

"Now faith is the substance of things hoped for, the evidence of things not seen."

Jim

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Sounds like I need to disassemble and clean/reoil. What do you guys recommend as a degreaser? Would denatured alcohol work? I have Leslie oil in stock.

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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I used a lot of Qtips and denatured alcohol. Leslie oil should work fine at the end. I'd take the slow motor out and just look carefully at it - feel the shaft and turn by hand to see if anything is binding. Make sure that the spring is pushing the rotor up when the motor is not running. Wash out the bearings with alcohol, then relube with a small amount of oil. See if anything seems to be binding.

Howard Grand|Hamm SK1-73|Kurz PC2|PC2X|PC3|PC3X|PC361; QSC K10's

HP DAW|Epi Les Paul & LP 5-str bass|iPad mini2

"Now faith is the substance of things hoped for, the evidence of things not seen."

Jim

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It probably won't hurt anything to leave the motors alone, but swapping the stacks is doable. You'll need to remove the slows from the fasts and remove the fasts from the brackets, and install on the other brackets and keep the upper and lower slow motors in those places, IE swap them to the other fast motor if you swap the fast motors around. Oh, and you'll need to swap the pulleys of course.

 

TP

---

Todd A. Phipps

"...no, I'm not a Hammondoholic...I can stop anytime..."

http://www.facebook.com/b3nut ** http://www.blueolives.com

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Okay, found the crackling issue. There was a small wire mixed in with the spring in the armature, not sure how it got in there. Removed that and the crackling is gone, but. . . .

 

After I reinstalled the motor I noticed that my bottom rotor changes directions when switching from slow to fast. I'm no expert on Leslies, but I'm pretty sure it's not supposed to do that! Can someone tell me what direction the bottom is supposed to spin in relation to the upper rotor? Obviously I need to flip one of the bottom motors around. . .

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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So counter-clockwise for the upper and clockwise for the lower? I can swear I put the upper slow motor back exactly as it was assembled, WTH???? Does the picture at the top of this thread look right to you guys?

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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That's correct, CCW upper, CW lower.

 

Any idea why the lower rotor would be switching directions from slow to fast? Does how the motor is plugged into the amp affect the direction it spins?

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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Shouldn't, but the motor you have shown here is also not the stock set for a 251. Who knows how it was jury rigged. One of those motors, either the fast or slow is hooked up backwards. If the the fast speed rotates counter the direction of the horn, then the slow speed motor is at fault. If the slow speed is correct, that the fast speed is wired wrong.
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If I exchanged the top and bottom armature parts around, would that affect the rotation direction? Aren't these parts exactly the same? I know the drum that rotates inside is correct because I remember the "blades" on it being down.

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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Okay, looks like I have to switch the parts around. Does it even matter which side the oil holes are on the armature? I really dislike taking these apart (with all the spacers/washers/nut) so I want this right the second time around!

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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I think I have this figured out. I believe I put the actual motor in upside-down. The armature has nothing to do with the rotational direction of the drum in the motor! I wish they would put a Top and Bottom Label on these motors, gotta remember next time that the wire leads are on top!

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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If the motor is upside down, the spring that moves it out of the way when not powered doesn't work - and that would definitely result in dragging, noise (and eventually worn spots on the O-ring).

 

Howard Grand|Hamm SK1-73|Kurz PC2|PC2X|PC3|PC3X|PC361; QSC K10's

HP DAW|Epi Les Paul & LP 5-str bass|iPad mini2

"Now faith is the substance of things hoped for, the evidence of things not seen."

Jim

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Well, got it installed again correctly as it's rotating in the right direction at both speeds. Unfortunately there is still a rattle in chorale mode. I even replaced the three rubber mounting grommets where it attaches to the bracket. My local Hammond tech told me to tap on the bearings with a screwdriver handle but that doesn't help at all. I had to order new mounting grommets for the fast motor (my rubber disc I inserted was raising the motor which was causing the rotor belt to rub against the wood shelf) as my local hardware store didn't carry the right size so this project is put on hold for now. Guess I need to just play everything 888888888 so I don't notice the noise. . .

'57 Hammond B-3, '60 Hammond A100, Leslie 251, Leslie 330, Leslie 770, Leslie 145, Hammond PR-40

Trek II UC-1A

Alesis QSR

 

 

 

 

 

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