Hammond M3 - intermittent crackling

[mpscholle]

Still finding a lot of different crackling sounds. Sometimes you don't hear it when you only play a single key, but if you play a cord you get the cracking. Sometimes it is when the vibrato is on sometimes it's off.

I have tried to fix some of these issues:
- Flipping switches many times
- Cleaning tube contacts
- Cleaning drawbar contacts

I recorded this example, but realized the vibrato was turned on. Here is an example:

https://drive.google.com/file/d/1dpX...w?usp=drivesdk

[tpappano]

It kind of sounds like something in or on the organ, or in the room, is resonating and vibrating with the notes you are playing. You can hear a slow 'beat' because whatever is buzzing is vibrating close to, but not right on pitch with the organ. Check for loose cabinet screws, parts, etc. It could also be the amp being on the edge of distorting at the volume you are playing at. Does it go away if you reduce the volume slightly?

[Silken Path]

Can you get somebody to put a hand on (1) the phenolic-like cover over the generator and (2) that big round matching transformer cover to the right while you play?

It doesn't sound electronic or electronically amplified to me.

[mpscholle]

I will do these tests tonight thanks everybody

[Jyvoipabo]

Good evening,

It looks like the organ picks up a radio broadcast station.

I've heard something like that before.
I don't remember where it come from.
May be a problem with a tube.

JP

[mpscholle]

We verified that it's not picking up any radio signals or anything outside..

we've also found that the upper manual does not have the crackling only the lower manual has it.

Volume doesn't seem to make a difference but obviously you can hear it more with the volume turned up.

When the throttle switch is turned off there is no crackling at all.

[Jyvoipabo]

Good evening,

In a hammond all the ground wires are connected in a single point.
May be one is bad.

Run a wire near this common point and try to connect it to the metal parts.
If the noise increases, you have created a ground loop and that's normal.
Look for a place where the noise disappears
Do not forget the engine casing.

JP

[mpscholle]

I did some work.. Cleaning the Vibrato brushes.
No luck. Here is some better audio.

JP: I still need to try your suggestion. But first... Thanksgiving Turkey!

https://drive.google.com/file/d/1t1c...ew?usp=sharing
https://drive.google.com/file/d/1kSI...ew?usp=sharing
https://drive.google.com/file/d/1KNO...ew?usp=sharing