Piano, Organ, and Keyboard/Lowrey tbo-1
QUESTION: My lowery organ has a problem. When I put the upper to lower tab on. The D#1 and E1 are combining there notes and playing the same notes on the lower manual when I press either key. It doesn't do it on the upper manual. But I do notice wen I turn on the long sustain tab. The D# sustained note rises slightly in pitch when I release the key and the E note pitch slightly descends on the upper manual. . I opened up the organ and checked the diodes put none tested bad. Any ideas?
ANSWER: Hello Steve! The TBO-1 was built in '68 and used transistor divider circuitry. It sounds like you might have a bad connection or a load problem. If a bad connection develops, a load placed across it can cause a dip in a critical voltage. This can affect the pitch of a note. If all the D# and E notes are affected, the pitch source becomes suspect. If the problem is limited to a single note or two, then I'd suspect the output of the respective divider...and whatever circuitry it feeds into. The Upper to Lower stop increases the load on the oscillator circuitry so it is not surprising a detuning occurs. The question is whether the fluctuation is the result of a bad component or simply a poor connection or even a crossed connection.
A simple technique for troubleshooting is to turn the organ on, hold down the bad note (such as E1) and begin gently probing the components that make up the D#1 and E1 tone sources. Use a wooden or plastic stick as a probe. If you bump into a bad connection, you will hear a sudden change in the note's pitch...hopefully for the better.
It would be helpful to know if the D# and E pedals are affected also.
Lastly, check for obvious problems like metal paper clips that could be resting on some circuitry and visually check the keyboard contacts for damage, shorting or other foreign objects.
Aside from this, you may need to call in an organ technician who is familiar with this technology.
---------- FOLLOW-UP ----------
QUESTION: Thanks for the quick response.
Just wanted to follow up and let you know that the D# and E Pedals work fine. It seems to be only the Single keys D#1 and E1.
also just to let you know and to see if this is related. Let me see if I can explain this right. If I turn on the AOC tab to put it in AOC mode. (Organ reset to normal disregarding the upper to lower tab and both keyboards are in it's normal mode with let's say a flute sound) I know that pressing the keys on the lower Manual help shapes the cords on the upper manual. With out there being any stop tabs "On" the lower manual producing no lower manual sound. the C note plays the upper manual C note and makes a sound. it does it on any C key I press on the lower manual but it only plays the same note(C2). it also makes sound on the D# note (which right now plays the combined C#, E note previously talked about) when any of those keys are pressed. the source of the sound seem to come from the upper manual.
I hope that made since. do you think it is related?
I suspect you have more than one problem going on. The first thing to do would be to check the power supply voltages. In an organ that is over 40 years old, the electrolytic capacitors begin to deteriorate, either shorting or opening, particularly in the power supply. This can cause a significant shift in the various voltage outputs which can result in the organ doing all kinds of strange things. Because the power supply is the "heart" of any electronic device, it is paramount that it functions correctly. Since you have a number of things going on, it all could be due to an incorrect voltage.