I'll do my best for now; I may have to give you more details/info depending on how you clarify these issues as per my comments, so here goes...
Glenn:
1. The Main stops sound out of tune, or possibly some of the keys just play the wrong octaves, making it sound funny.
This happens all the time. The main voices are produced by a square wave generator/divider, and to get the wave into the proper staircase formation for voicing, several octave pitches are keyed for each note (at varying levels). The problem is the horseshoe cinch connectors the generators plug into are unreliable. So, in csome cases, you will get only the harmonic octaves and not the fundaental octave, so the note sounds an octave too low or high - and "weird". Remove each TG41 generator from the cinch connectors (carefully - and take note of which generator board plugs into which slot), clean all the contacts on the generator boards AND the cinch connectors, and re-seat the boards. The problem will happen again sooner or later. It COULD be that the keying transistors for some of the notes on the board are bad, or it COULD be that one of the divider packs has gone bad (which would affect all lower octaves for that note as well), but try cleaning/reseaating and take it from there. The TG-41 generator set consists of 6 individual boards, each handling 2 pitches, that plut into a backboard - from the back of the organ, these are on the LEFT (edit) side. I'm still stuggling with my set as well.
Glenn:
2. The Tibias sound OK for the most part, but I have noticed with some notes, not all of the sounds play immediately when the key is pressed down (note: this delay problem may affect the main stops also, I've just noticed it more with the tibias because I play the tibias when I want to practice since they actually sound decent).
Intermittent and delay are two separate issues on the tibias. An intermittent note is probably just due to dirty contacts. THe tibias use a bussbar/contact wire mechanism. If you play the same note over and over again, that should clear up an intermittent note problem. THe organ must be played regularly or else the problem will return. But, that's no big deal. If however you have a tibia putch that slowly fades in (starts very soft then gets louder), or a tibia pitch that is altogether weak, then the 230-ohm emitter resistor in that oscillator's circuit has drifted upward and needs to be replaced. The tibia generator set is huge - 12 separate chasis with individual oscillator coils for each octave pitch. From the back o fthe organ, these are on the right side. They are probably TG-15 (or possible TG-10 in earlier models). TO remove a tibia chasis you would also have to remove the front of the organ and carefully pull out the two plugs that attach to the generator chasis. Be careful when you plug it back in - it matters which one you plug into the top and bottom rail. Let's hope you just have intermittent notes and not delayed notes - that's much easier to take care of. NOTE: If you have multiple tibia pitches turned on, and you press the key down slowly, keep in mind that all the pitches may not be activated simulataneously because each pitch has a separate contact wire. That's normal.
Glenn:
3. The reverb button doesn't seem to do much. It sounds like it wants to do something (slightly different than the omega button), but it doesn't sound like reverb to me.
The "Omega" percussion system only affects the top manual. Also, it only affects the tibias. The "omega" button itself cancells any of the reverb/sustain functions. Buttons reverb, percussion short, and percussion long will apply varying degrees of sustain to the note (from shortest to longest respectively) - will increase the decay time when the note is released (so it is NOT percussion per se, but sustain). Reverb is really only noticable when you are playing slower music and you will hear it better when going from one held note/chord to another. Percussion pre-set will apply a long sustain but also cancel out any main/complex voices. Chime will cancel out all voices except for four tibia pitches (one of which, the 6 2/5, is "hidden" and only used as the chime humtone) and apply the long sustain, and turn off the fast leslie if it is on. If you do NOT hear a pronounced reverb or sustain effect on the tibia pitches on the upper manuals when you use the buttons I mentioned, then chances are the sustain capacitors on the tibia generators have gone south, and need to be replaced.
Glenn:
4. I don't yet have the schematics for this organ, so I'm not totally sure what the little lever is underneath the manuals (a pitch bend lever maybe?), but it doesn't seem to do anything.
Your organ is equipped with the optional "electro-mute" - it will only work with the "Tuba" stop. It is a pitch bender. Don't know much about it as my organ doesn't have it.
Glenn:
5. The physical connections of the pedals mostly don't work (if you take the pedals off, pressing the little pads on the actual organ works). This might be the easiest problem for me to fix.
THese are tricky - make sure the pedalboard is snugly in place, and also that the actuator pins attached to each pedal reach down far enough - adjustable with an allen screw. I was having a lot of problems with my pedalboard and had to remove the top cover of the pedalboard to get it far anough into the slot for the pins to make proper contact with the felt-covered pedal actuators. I have no easy answers for you - trial and error. Just make sure you don;t lower the pins too much or you can damage the actuators.
Glenn:
6. When the organ is on, the left (fixed) speaker has some excessive noise. At first, I thought it was the rotor, but it is coming from the fixed speaker. It might even sound like the signal is picking up some interference from whatever that small rotating thing near the dead center/bottom of the back of the organ (forgive the lack of proper term here - when I get the schematics I'll update with the correct term).
That little motor that always spins is the electronic vibrato/tremolo for the MAIN channel only. It consist of a lamp/rotating shield/light sensitive resistors. It does both frequency and amplitude modulation. See if the noise goes away when you turn the "Main Tremulant" tab off. Make sure the lamp is on and adjusted properly. Also what does this "noise" sound like? Is it crackling? hum? Static? If it is a pulsing noise then chances are it is coming from the vibrato mechanism.
Glenn:
7. Some of the keys stick - they probably just need to be taken apart and cleaned up.
If you mean physically stick, this is probably because the rubber upstop bushings under the key-channel have broken down - they can become hard and sticky. They are not easy to get to - I can give you more info on that later. If you are seriously going to refurbish and keep this organ, I strongly recommend that you replace ALL the upstop bushings - it will make a world of difference in the key action.
I hope this helps for now. Please follow up. I'm very happy another Model D is being used and cared for!
-jim
Jimmy Williams
Gulbransen Model D, Leslie 204, hobby organist/technician