Hi, I found a Wurlitzer organ that I am thinking of buying but the D, D#, F and F# keys don't work of the upper and lower key boards. The keys sound responsive but don't make the noise that an organ key should make. Is this organ worth buying? How can I fix it?

I would take the pedal board apart, repair any damage and put it back together again.

https://www.organforum.com/forums/showthread.php?50109-Wanted-Wurlitzer-Omni-6000-Keyboard-Computer
https://www.instructables.com/id/Repairing-an-Electronic-Organ/
http://www.casiomusicforums.com/index.php?/topic/13338-wurlitzer-organ/
http://forums.musicplayer.com/ubbthreads.php/topics/2332520/all/SK_1_and_2_Tips_Tricks_and_Oth

I think you are speaking of an organ.
Your organ has electronics inside it, and I believe the circuit board for the lower keys has a broken connection.
You should find an electronic organ repair place.
I just looked online and found several places.
Since you may be near to none of these, relay on your computer to find someone who can repair this circuit board.
They will have to tell you how to take it out of your unit.
God bless your efforts.

You can find a tech in your area on this site-p

Electronic Repair Services for the Entire Music Industry MITA International

Your best bet is to contact Mark Morelock at-
Morelock Organ Parts MITA International

On organ mode, in general, almost all brands of the modern keyboard, velocity setting is not enabled. Setting velocity is used to determine how much the level of the sound that follows how strongly you press the keys. It is really just to imitate the sound of vintage organs, which in the past, electronic organ technologi not use the velocity on the keys. So, how strong / slow we press the keys, the sound level will remain the same.
At the Piano mode,modern keyboard using setting velocity. This also to imitate an acoustic piano, which, if we press the keys slowly, the sound level will be slow as well, and vice versa.
So, in your case,at the same volume slider, try to play on the organ modes, note level. Moving to the piano mode and press the keys securely powered (full power). Then the sound level should be equal to the organ mode.
On modern keyboards, also included organ sound that added velocity setting. Usually found on the user bank.

I have one with the same problem and am trying to find a solution too.

Please leave a response on this website if you find a fix and I will do the same.

Good Luck

hi there try Hold down the 4 Lowest Keys on Upper Manual C C# D D# hope this helps you

Servicing is obviously required. By the symptoms, I think a bad electrolytic capacitor is the likely culprit. One other possibility is contamination, including an insect has gotten into the works and causing a short at some point.

If this is the kind of organ with the wire sticking out of the key that makes contact with the bus bar to create the note you will have to make sure that key is operating the same as adjacent keys. The busbars have to be clean and the contact wires have to be clean. Sometimes when cleaning the wires they will spring out of place and not make contact with the appropriate bus bars. Check that key against the rest and see what you find. Hope this helps.