Juno106 repair question

Hello - first post. Hoping I can find some help. I’ve been restoring my first synth - a Juno 106S / HS60 a friend gave me. It had the standard issues - bad voice chips, crumbling fader gasket material.

I’ve cleaned and lubed the faders, replaced a lot of the power supply caps, and got 2 replacement voice chips for the ones that obviously tested bad. I’ve swapped these in and they sound good.

I’ve gone through and done the tests + calibration procedures, and still have an issue.

The chip in my voice chip 1 slot (i’ve done the acetone strip on a couple of these ones i replaced, and i’ve been swapping them into that spot) - when i test on rotary mode it sounds normal until i slide up the SUB slider and then it doesn’t sound on voice chip 1. The analog renaissance site test procedure says it may not be the voice chip - it may be a bad multiplexer in front of the chip. What is the multiplexer? Should i just order 1 more of their replacement voice chips and swap it in?

Another symptom - even though i have tested all the supply voltages as correct (15, -15, 5v etc) on the module board, the voice chips during the calibration procedure are unable to get to the 4.8V peak to peak on VCF resonance and 6V peak to peak on VCF gain. Even with the variable resistors maxed out, they can only get to maybe 75% of that spec value.

Any ideas? Is it a bad voice chip pulling down all the voltages? I haven’t replaced any caps on the module board.

Any help is appreciated.

additional test - i did the sub oscillator test in rotary mode per the service manual and it’s silent for voice 1, but works for the rest.

This is bumming me out. Bought a new voice chip and a new wave generator, replaced both, same symptom (no SUB out on voice chip 1). Also replaced the 4052 multiplexor for voice chip 1.

Problem still exists. Any suggestions? Looking at the diagram it seems like IC1, IC17 and IC24 all are in the sub path after the above parts i replaced. IC1 and IC17 are M5218L op amps. IC24 is MC14051B.