![]() I've found that in divider circuits, the problem is almost always a bad transistor, but capacitors can be the problem, too. If the board is difficult to remove or access, it might be best to just replace all transistors and capacitors and be done with it. For dividers, I usually just replace one transistor, test, then replace the other. On the Vox Jaguar/Howard/Doric organs it shares a circuit card with the Vibrato circuit.Īt this point, you've identified the problem area(s), and all you have to do is replace the failed components, right? Unfortunately, I know of no way to determine which component is bad. Bass Divider circuits are usually on a separate card by themselves. In this case, if the divider circuit is bad, the whole octave will be affected. If the octave is monophonic (only one note plays, no matter how many keys you press), then there's probably a single Bass Divider circuit that serves the whole octave. Generally, if a bass octave is polyphonic (you can play more than one note at a time and they all sound), then it's driven off the lowest divider(s) in the chain, and can be treated like the rest of the keyboard for diagnosis and repair. ![]() ![]() On some organs (the Rheem Mark VII comes to mind), there's a combination of these two. On others, a separate, single divider circuit serves the entire octave(or maybe two). On some organs, the bass notes are just additional divider outputs, but filtered differently. We've been ignoring the bass octave(s) til now, because they can muddy the waters of diagnosis. The bad news is, if you have more than one bad divider for a given note, you can't test the lower ones until you get the ones above it working. The good news is, once you fix that divider, there's a good chance the lower notes will suddenly come to life. Divider problems cascade - once you have a bad one, none of the notes below will play correctly. ![]() If a note stops functioning that worked in the previous octave, then there's your bad divider. Continue to do that until you hit the 16' foot tab, which will be the lowest divider in the chain. When you reach the bottom of the keyboard (NOT descending into the Bass octaves), then turn off the voice tab you have on, and turn on the next lowest even footage, and play the same note (the lowest one short of the bass octave). The first octave below the top octave (with the highest even footage on) is the first divider, the next lowest octave is the 2nd, and so on. With the same tab on as previously, play each successive lower octave. There may be as many as 5 or 6 dividers for each note. From here, we'll test each divider circuit. ![]()
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