Archive of the former Yahoo!Groups mailing list: OldSynths

Hi everyone,

I took delivery on my ARP Pro Soloist today. I knew it would need
repairs when I bought it, and here's what I've discovered so far. I
would really appreciate any suggestions on the next diagnostic/repair
steps. I have a hunch this is not going to be that complicated.
(crossing fingers)

Here's the problem: It powers up correctly. Every key triggers a
sound, but the pitch does not change from key to key. The sound it
∗does∗ make is a very low cycle tone, much lower than any keyboard
should make. It does not seem to be an LFO, because: The pitch
changes in octaves (roughly) as I move the octave shift lever. Of
course, the pitch is so low to start with that the "normal" and "low"
octave settings are just clicks. The pitch does NOT change, as far as
I can tell, when I adjust the tuning trimpot, nor does it respond to
the front panel tune "knob".

The preset switches DO change the timbre of the sound, as if the
filters are working correctly. The volume slider works normally. The
"touch sensitivity" switches act as they should EXCEPT for the pitch
bend, and possibly the vibrato (hard to tell with such a low pitch
though). Portamento does NOT seem to work.

The presets I would expect to be in a lower octave seem to be so, e.g.
"Bass", "Tuba".

What I've done so far:

--I replaced the aluminum caps in the power supply, and the output from
the power supply is normal.
--I very carefully cleaned all the oxidation off the J-wires and the
contact bar. Key triggering is almost perfect as far as I can tell.

Can anyone offer any suggestions? I have a couple sources for spare
parts if I need them--I'm just not sure what to test/fix next.

Thanks very much,
David Shoemaker