Servicing a Leslie 122 – Part 1

Leslie Cabs

Isn’t it time you serviced yours?

Well it certainly was for me. I’d had my Leslie 122 for about a year and it was kind of rough and ready you know? My technician and I had started work on the electrics side of things, changing the modified locking 8 pin input, installing separate power/earthing and changing the switching relay down to 12 volts – for the whole not killing yourself thing – (more on that later). Anyway, I did a little recording with it and noticed how the microphones picked up all the little squeaks and bumps that you find on old mechanics. From then on either it had gotten worse or I couldn’t not hear it so I visited my old friends at Tonewheel General Hospital and placed an order for a few parts that I hoped would help the sound but also the longevity of the cab in general

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In the end I went for a replacement bass rotor belt, a load of bearings and the bearing idler that goes on the tensioner arm. My theory was to deal with all the moving parts first. I already had a few spare O rings for the motors and a bucket of Leslie Oil so lets strip it right down and replace worn parts as we go, see what happens!

The Leslie Top Rotor

Before we start lets do the usual disclaimer: People can die messing around with unearthed machinery. Make sure its unplugged. Handle with care and ensure that you put things back where you found them. If in doubt at all I have to say, get someone else to do it. That said, its not too difficult if you show it some respect.

In short then, what we need to do here is get the motor out, strip it, oil it and change the O ring. Its worth getting the horn off and cleaning it up too and change the bearing idler. The good news is that its just mechanics so get a screw driver out and a camera phone and start unscrewing things. If you are unsure take photos to help you replace it later. Lets start with the motor

Leslie Speaker

Take all the wooden bits off the Leslie that are stopping you from getting to the spinny things. Also, disconnect all of the wires coming into the amp. Always good to take a photo here, no matter how many times I do it I always end up connecting it backwards first time if you do it by memory. Its my age I think! Anyway, now we can remove the motor. This is held in place by a couple of wing nuts as seen in the photo above. The third wingnut is for the tensioner don’t mind that for the moment. Once lose you can disconnect the belt and the wiggle it free and out via the middle not the top. Getting it out makes is much easy to oil the easy bits but also possible at all to oil the difficult bits.

Got it out? Good. Get it on the bench (or in my case the top of the Leslie) then and we can take a look

Leslie Speaker  Lets have a look:

Leslie Speaker Motor
Leslie top motor

Take off the power section to reveal the mechanics (4 bolts from memory). This will reveal the state of the O ring.

Leslie Speaker Motor
Power assembly off to reveal the O ring

If you have gotten this far then replace the O ring, why wouldn’t you

Leslie Speaker O ring
New O ring next to old O Ring

Now that you have the motor in your hand you need to ask yourself when it was last oiled. If the answer starts with a 19 then you are in a good place to save this from extinction and get it greased up. Below is a diagram of the motor and where to oil (lifted from a great site go visit!)

Leslie Speaker Oiling

Basically there are a couple of easy places to oil and a couple of less easy places. For the easy places just get cracking:

Leslie Speaker oiling Leslie Speaker oiling Leslie Speaker oiling

For the difficult places in stead of stripping everything down what I did was ran some oil down the shaft of a screwdriver into the oiling point.

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Removing the horn and driver, oiling and generally getting all the muck out is a pretty simple task too. In the case of oiling you actually get the “oil here” advice for once! Just removing the bolts, dropping the driver down and pulling the horn up through the top. There’s some jiggling to be done here and it makes your arms ache in places but it’s simple enough stuff. Once out give it a clean:

Leslie Speaker Leslie Speaker Leslie Speaker Leslie SpeakerThe last thing to do before we put it all back together again is to replace the idler bearing. Well, this was interesting. The replacement bearing was smaller than the piece I took off and I had a head scratcher for a while until I relealised that the replacement actually went inside of the main part

Leslie Speaker



Leslie Speaker
Replacement bearing, is only the inside part

There’s a few ways to replace this part and I’ll tell you how *I* did it, other and better ways are available. I went to my friends workshop and pushed the centre out using a punch and slow compression of a vice. I’ve been advised that heating up the outside may also help it come out more easily too. Re-fitting the new one is the reverse or removal and that’s it, we are done.

Hopefully you have kept track of the order of things here, to be honest you can do the motor then replace it, do the horn then replace it and then the idler and in that sense you don’t have too many bits lying around at the same time do you? Less to forget where to put it.

You should have by the end of this process a nice and quiet, non slippy top rotor…

Anything I have missed? I’m doing this as a public service from memory as I was directly messaged about it recently. Ah yes, the bottom bit. No problem. Well, some problem as it turned out. I’ll do a separate post for the bottom rotor and maybe even one about the light ‘upgrade’ that I put into all of my Leslies to make them more a part of the stage show.


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