bassik Is it possible that the J10 outs are on other ADC channels?
they are definitely the L and R DAC channels. It is also very possible that breaking the pads on J9 will have cut the trace that feeds J10. Are you 100% positive that they do not work at all? There is a resistor in series (which would make them hard to hear via headphones), and they are fairly low for regular eurorack standards (about 1.8Vpp). It is fairly hard to get those signals otherwise, as they come straight from the codec, which is a QFN (quad flat no lead, that is: very hard to tap a wire onto its pins) part ... :
As mentioned, an alternative is to use the headphones out from J4 (although these are not DC-coupled).