Opus 3 Troubleshooting

[Pie]

I'm new to this forum so apologies if I've posted in the wrong sub.

I'm working on an Opus 3 (for my son) and the brass section is not generating sound. The organ and string voices work (strings may be a little low on output but lower priority). I've checked some of the basics like power supply (working properly), visually bad components, bad traces/solder joints and everything looks ok. Signal is present coming off of the organ/brass mix slider up to R163 (R163 checks good) and then nothing. I'm at the point of replacing various IC's but looking for any insight before I start ripping and replacing.

Disclaimer, I'm good with a soldering iron but this is a fun hobby for me and I have limited debug skills.

[Thouggerve]

Check IC10 and IC11 as they’re key for brass voice