Need Help, Preset Keys Make a Tone

[thegreathunter1]

Hi All,

I have a Hammond C2 with everything working but when I press a Preset Key for the top row, a tone is generated for every Preset and it changes slightly with the Preset. I very good with electronics and have the schematics but was hoping someone with more experience could help me out. If I've forgotten any information, let me know.

Thanks!

AGreer

[handyczech]

Do you mean with no notes played? If I understand you correctly, you are describing the sound, more or less crosstalk, as one preset is coming off and the next one is coming on. If you press 2 or more at once the same or similar sound will appear continuously until all but one is unlocked. I have heard this sound in varying degrees on every generation of tonewheel console I have ever played and I never gave it a thought beyond being the nature of the behavior of the matching transformer. The tone you hear seems different due to each preset having different harmonic components that interact with each other. If or how to get rid of this tone would have to come from other contributors on this site smarter than me.

Larry K

[thegreathunter1]

Hi Larry,

Yes, with no notes played a tone is generated when only one preset is selected, it just changes pitch with the different preset. It's only on the top set of presets and is at the same volume as the notes played. I should be able to take a video tomorrow but I'm not sure how well it would post to this forum.

I'm by no means an organist but I'm decent at electronics repair but not as familiar with tubes. I'm thinking that either a filter cap is bad or something is shorted or disconnected. I just don't know where to start looking...

Thanks,
AGreer

[Jaim]

This is a cypher which probably means you have a stuck key contact. With the Bb preset selected, try and match the tone to a key and DB. Once you do, hit the key repeatedly to see if that will free it up. sometimes the key actuators will get stuck.

Jim

[handyczech]

As stated, set up the B or Bb and pull out the drawbars for that key, one at a time, and see if the stuck tone appears. You will then be able to tell which key may have a mechanical problem. It may be the stuck leaf on that key for that harmonic, and staccato playing of that key may free it. It may also be that a clump of debris may be preventing the contact from rising to rest completely. You would then have to remove the music desk/rack assembly, and remove the drawbar assembly screws and tip it up to gain access to the row of screws which hold the keys on. You would then loosen the screw for the offending key and adjacent black keys if applicable. Remove any debris. It might be wise to fire up the organ to make sure the tone is gone. It is less likely that the felt covered tongue on the underside of that key has a problem. The tongue can be carefully bent slightly upwards to depress the contact less far, but this is a ticklish but not dangerous process. I would doubt this is any sort of electrical component problem as there are no discrete circuits that affect one harmonic on one key.

[thegreathunter1]

Hi Jim and Larry,

We were able to find it and fixed it! We did as suggested and found the tone that was stick and took it apart and found a ton of built up dust and oxidation on the contacts. We wiped it down and used Deoxit to clean the contacts. It works like new.

Thank you!

AGreer