Yeah, that's the one I saw, but I found it at Korg's Vox "vintage schematics" page. Looks a lot like our friend the Phase 90.
If one opamp's had a massive burn, I would not trust the others. Opamps are too cheap. FETs may have lived. You may be able to check them out of circuit. Tossing them into the JFET matching circuit would tell the tale.
I actually found a different Korg phaser schematic that looked a
bit more similar, the only thing that has me scratching my head a bit is there is a trace for a wire going through a 2M2 resistor, a bit like the 3M3 goes to the Phase 90 gates and a trace that connects to the sources like the Phase 90 LFO, then a trace from the buffered LFO & the Zener voltage... my head tells me, depth 3 goes to LFO out, depth 2 to the sources and depth 1 to the 5v6 zener to blend between LFO output voltage and a fixed voltage... but the unconnected 2M2 seems odd.
Yup, all OpAmps have been replaced, I think the LFO one survived and my mistake was that the rate pot wire fell off without me noticing as I just tacked it in case I made a mistake, also the input & output one may have as it used a BCE transistor buffer input and I twisted a 2N3904 to fit and despite checking again and again, two of the legs were touching even if I couldn't see it and that OpAmp was providing a very weak output... but it would with a weak input, not so important now they're gone.
Anyway, at the moment I tacked rate direct to the sources and have tremolo, at the 1st phase stage a tremolo with dry signal, at phase stage 2, just wet tremolo, FET bias did have an effect at one point but I can't remember how I had it all hooked up and I think that was because of a mistake and there was a lot of oscillation with certain setting, with voltage moving erratically on every pin of the FETs, I think they might be a tad dead.
I may throw the FETs in a matcher to see if they're worth keeping but it's probably easier to match 4 FETs from a fresh batch than 2 or 3 to the original ones with stubby de-soldered legs
