hugh wrote:
I have an opportunity to get a Lowry Celebration C-500 organ.
Unfortunately it has some problems. I believe that the instrument was
made in the late 1970s.

1. All C# and A# are out. Mutations on the same notes are OK. I
assume that it is in the tone generators some place - possibly even the
same chip.

2. There is weak and distorted sound on pedals and the lower keyboard.
Upper sounds great except for the dead notes.

Does anyone have any ideas on these two problems and would it be worth
fixing?

I'd look to the divide down circuitry. There is a master oscillator and
all the tones are derived from that through divide down. Sounds like a
couple of dead outputs.