Sequential Split-8 repair

[Barry L Klein]

Anyone have experience repairing/using a Spit-8?  I've got one in which
the pitch bend wheel doesn't act right.  As you raise the amount the pitch
tracks ok for awhile and then pops up about an octave.  You see this pop
in control voltage to all the 3394's(pin 2).  The voltage goes through a
4051 and then gets distributed to a dedicated 4051 for each voice.  All
voices do the same thing and the signal that gets sent to each one's
4051operates linearly.  So why the pop out of each voices 4051?  Weird. 
There is a negative supply voltage set by a LM317/337 at -6.6V, which
really measures -6.4V...  I was thinking of tweaking that to see if it
made a difference.  I'm planning on forcing the 4051 selects to select
just this switch path to debug it and that entails removing and socketing
a chip to gain access to the lines etc. - a little messy so I thought I'd
ask if someone here had any experience with this before.....

Also one of the 5V regulators has a 220 resistor tied from its output to
its input.  With no load, the output raises up to 7V!  Why did they do
this(its designed in this way)?

There was no service manual made for this synth.  Only schematics, which I
have portions of, and an operations manual, which I don't have.

Barry