L122

[eric appla]

Hello folks,

i have acquired last week hammond L122. Following the initial inspection there was no sound coming out of the upper manual and no sound from pedal. I resolved the problem by cleaning the valve sockets and all is working now apart of 2 registers where I think it's just the wire cam off from the end of the draw bar. There are 2 stuck black keys on the upper manual and one bad loose sticky white on the lower manual.
Organ is now making sound but after some time there is substantial amount of hum @around 50Hz/100Hz harmonics. I take it this will be most likely due to the PSU Mallory caps being past their best. The generator itself was rather loud and I put Hammond tone wheel oil onto both cups as well as into the two tiny cups on the blue motor. However after standing switched on for some 3 hours generator would start deteriorating rather then improving with added lubrication. It sound as if it was not spinning at constant speed.

I have fixed various Organs and I'm confident in finding the electrical issues without a problem however the tone wheel generator is something I'd like to get your guidance on.

What is the best course of action? Is it something you'd normally remove, clean and re-lubricate accordingly? Can this be done without removing all hundreds of wires from the generator assembly?

Thanks and Kindest Regards
Ondrej

[peterb_2795]

Ondrej,

Current wisdom (as you will see from many threads on the topic of stuck, sticky, noisy and squealing generators) is oil and time, oil and time. Be generous with the oil initially as it has to work its way through the hundreds of wicks and then into the bushings in the generator. If after a couple of weeks, you do not see real improvement, then it might be time to consider other treatments to clear through and waxy or hardened residue in the wicks.

Oil and time, oil and time ... :)

[eric appla]

thanks, oil and time it is :)

[enor]

oil and time. plus: (since it's an L-100 seies)

* replace motor run capacitor
* clean all white molex connectors (if you find it's NOT broken drawbar wires, which it likely isn't)

- - - Updated - - -

... clean and re-lubricate accordingly? Can this be done without removing all hundreds of wires from the generator assembly?

In the case of the model L-100, lubrication access is _very_ good without desoldering anything. Stand the entire organ on end and remove the sheet of itchy insulation material under the generator. Now you can sit down comfortably on the floor next to your organ with direct access to every bearing.

[eric appla]

oil and time. plus: (since it's an L-100 seies)

* replace motor run capacitor
* clean all white molex connectors (if you find it's NOT broken drawbar wires, which it likely isn't)

- - - Updated - - -



In the case of the model L-100, lubrication access is _very_ good without desoldering anything. Stand the entire organ on end and remove the sheet of itchy insulation material under the generator. Now you can sit down comfortably on the floor next to your organ with direct access to every bearing.

good advice, thanks for that

[Jyvoipabo]

Hello,
You can turn the organ body bottom over head which allows access to the mechanism without disassembling anything.
Then you can oil each bushing with a syringe and you will save time.

When the wheel stop by itself at least 7s after power off, it is OK.

But, the oil will not repair a faulty electronic component (Connectors, Tubes, Tubes sockets, Capacitors Resistors......
If the 5U4 is original it may need to be changed.
About the motor start capacitor :
It is a possible source of hum. If the can is inflated it is certain.
It contains dangerous oil (PCB).
Pay attention of the voltage if you are in 230V.

JP

[enor]

About the motor start capacitor :
It is a possible source of hum. If the can is inflated it is certain.
It contains dangerous oil (PCB).

Even worse: it can develop a short between one of its terminals and ground, effectively putting full mains voltage on all exposed metal parts of the organ. It is a rare failure mode, but it does happen - I had an L100P in my workshop that had failed like that, giving its owner a 230V jolt and sending him to the emergency room.

My strong advice: Never mind if it looks good or swollen - replace it anyway as routine maintenance, and replace with a different type which has an insulated plastic housing. Life is too short even without 230V shocks running thru your body.

Oh, and also - the most common failure mode for the run cap is that the organ drops down to the wrong pitch when warmed up; or that it starts oscillating (rising-falling-rising-falling continuously)

[alpine]

I've had the motor start capacitor blow up on my old L100. It's a messy and dangerous business. Particularly if you have the back off to investigate why all things are not as they should be.. It was getting red hot. The cap flew at high speed across the room and I was very grateful I wasn't in the way which was pure luck. Oil, burnt paper and bits everywhere...
And don't replace it with one that looks the same. They haven't been made for years and any replacement will also be elderly. Just get modern motor start capacitors from Ebay. If you can't find the correct value, then parallel up 2 to make the correct value.

[enor]

And don't replace it with one that looks the same. They haven't been made for years and any replacement will also be elderly.

Not true, new ones of the same type are readily available.

But I agree - don't use them. I use ceiling fan run capacitors - they have a nice plastic housing with a hole for a fastening screw. Very easy to use and very good.

[alpine]

Not true, new ones of the same type are readily available.

I think you mean 'old stock'...

[enor]

I think you mean 'old stock'...

No I don't. Genteq, for instance, still makes them:

https://www.genteqmotors.com/Product...DC_Capacitors/

[eric appla]

hi guys, I already purchased new run capacitor 1.5uF/600V, the new type with screw and will replace the original one. Since it is oscillating I take it this will cure some of the problems. Regarding the rectifier tube comment, it's been a while I dealt with those but don't they just blow fuses if bad? It won't cause hum or would it? I'll have a look with oscilloscope on amount of ripple after each capacitor but if it'll be similar to the last L100 I worked on those Mallory cans will be past their best.

[Jyvoipabo]

Hello,

In 230V50Hz it is a (hard to find) 1μ25 which requires the assembly of 2 capacitors in series with a resistor added on one.

If this capacitor is bad either : the motor does not start / growls / creates a ground fault / rarely oscillations.

The value of old electrolytic capacitors increases with time. Between 100 and 150% there is no roblem.

As it was said, you have to start with the oil and cleaning all the contacts and check ground circuit. If you have a tube tester it's good to check the tubes.

JP

[enor]

I use this type. 1.2uF is close enough (within the original tolerance span)

https://www.--------/itm/CBB61-450V-...LH_TitleDesc=0

[eric appla]

i made a typo, it's 1.25uF I bought, it was just over 1EUR from local parts shop

https://www.comarcond.com/wp-content...MKA-MK-450.pdf