Peavey Deuce VT Preamp Problem

[telecaster]

Long story short: This amp came in with 5-6 of the IC's physically exploded. Further exploration revealed circuit board traces burned open and the rest of the IC's had power supply shorts, plus some shorted diodes, etc. I fixed all that, repaired the +/- 15 volt supplies (I read Enzo's posts!), and then plugged new IC's. For the moment, I bypassed the analog switches, U17 and U18, with jumpers and signal traced both channels. The Normal channel has weak overall gain and the Effects channel is distorted and compressed - true with test sine wave or actual guitar. This is true at the preamp out jack, or the same with the tube power amp engaged (verified the jack loop is working correctly). I worked backwards through the preamp out and I come to the 478 (U14 in Effects and U15 in normal) ICs, which are CA3094 Operational Transconductance amplifiers (OTA). I also worked from the channel ins to the aforementioned OTAs, all the other op amp stages seem to be working fine, except these OTAs. I did some research on how they are supposed to work, basically a small current source to pin 5 controls the transconductance where the differential input voltage is converted to an output current. This current feeds the Post Gain control. Both channels have incredibly small output currents and develop only about 200mv peak-to-peak across their Post Gain pots with a 1KHz sine wave applied at the channel inputs, per Peavey's test conditions. I checked all the surrounding resistors, caps and diodes and everyone is in spec. Under test conditions in the Normal channel, U2B (a TL072) pin 7 has a 2V sine wave out, driving a 1/34 resistive divider to the OTA's minus input. It also feeds a diode, which half-wave rectifies it and provides the control current. The node where the diode CR10 meets the + end of the electrolytic cap C58 is sitting at about -2V in this scenario, which seems odd to me - I would expect it never to go below ground.
Does anybody have experience with debugging this circuit? Any suggestions would be appreciated.

[Enzo]

With U15 out of its socket, is ther still -2v at C58? I am going to assume CR10 is not in backwards.

ANy chance pins 4 and 5 of U15 socket are shorted together or their traces anyway? By my clumsy calculation that should result in just about -2v there.

Does C35 up at U14 behave the same?

ANd i assume you are using chassis as a refernce? When you measure that -2v on the + end of C58, what voltage do you see at the other end of it? SHould be ground, but is it?