Odd noise on a drawbar help

[Grasshopper]

Hello again all you experts!

I am having an odd problem with a drawbar.

It is the 8th drawbar on the second set, for the top manual.

When I use it with the drawbar presets (B & Bb) it works perfect.
When I switch to any other preset on the top manual, it causes a odd hum. I can also hear the drawbar note being produced.
Obviously, the more I pull it out, the louder the hum and note get. It is only the 8th drawbar this occurs.

What makes it even weirder is it seems I can make it go away by finding the "in between" spots on the drawbar.
I push it in a little and it goes away, a little more and it is back ETC.

Any ideas on what might be causing this issue?

Thanks so much for all your help and advice in advance!

The Grasshopper

[geoelectro]

Under each preset, there are 9 contacts for the 9 busbars. If a contact were to get stuck, say the no. 8 drawbar on the B preset, the no. 8 drawbar would be enabled all the time. If more than one preset is latched down at the same time, there is a noise that sounds like notes playing in the background and hum. A stuck contact on a preset, mixed with another preset would be capable of making a similar sound/noise. The only flaw with this is you say the B and Bb presets work normally.

Try this. Cancel all presets and pull out the no. 8 drawbar and see if it plays. Then, if it does, push the Bb preset with its no. 8 drawbar set very low. Now see if you get noise and if the lower set drawbar plays properly.

Geo

[Grasshopper]

ok, I have an update........

Upon turning up the Leslie nice and loud, I discovered I can hear the hum on every preset except the B.

When I cancel all the presets, the no. 8 drawbar (B preset) still plays but with no hum.

When I push the B preset, it plays perfect with no hum. When I push the Bb preset, it definitely has the same hum as all the other presets for the top manual.

Does this still sound like a stuck no. 8 drawbar contact on the B preset?
What is the best way to go about fixing it?
Would a busbar adjustment help?

Thanks so much for your help and advice so far!

The Grasshopper

Under each preset, there are 9 contacts for the 9 busbars. If a contact were to get stuck, say the no. 8 drawbar on the B preset, the no. 8 drawbar would be enabled all the time. If more than one preset is latched down at the same time, there is a noise that sounds like notes playing in the background and hum. A stuck contact on a preset, mixed with another preset would be capable of making a similar sound/noise. The only flaw with this is you say the B and Bb presets work normally.

Try this. Cancel all presets and pull out the no. 8 drawbar and see if it plays. Then, if it does, push the Bb preset with its no. 8 drawbar set very low. Now see if you get noise and if the lower set drawbar plays properly.

Geo

[geoelectro]

Yep. That sounds exactly like it. I remove all the keys. Then the cover over the contacts. May have to remove the left cheek block. Then, you will be able to see into the preset and hopefully see the stuck contact. Compare to the neighboring set of contacts. Then, I use a small dental pick or the like to pry the stuck contact up and back on top of the busbar.

Geo

[Grasshopper]

SUCCESS!!

Exactly how and what you described, thank you geoelectro.

While I am in here, is there something I can do to clean the contacts?
Would straight electronic contact cleaner do any damage or good?

The Grasshopper

Yep. That sounds exactly like it. I remove all the keys. Then the cover over the contacts. May have to remove the left cheek block. Then, you will be able to see into the preset and hopefully see the stuck contact. Compare to the neighboring set of contacts. Then, I use a small dental pick or the like to pry the stuck contact up and back on top of the busbar.

Geo

[geoelectro]

I usually stay away from cleaners. However, in certain circumstances I have used DeOxit D-5.

Geo