Collins 356Q-1

I'm trying to set up a pair of Collins 356Q cue amps to use as mic pres. The output is giving me an expected level of noise, but nothing is coming through from the input. I'm fairly new to modding/diy-ing (a few kits and modifying a Sta-Level for compression ratio and release times) so I might be missing something obvious in the schematic. From the description in the manual it looks like it should work without many modifications, though very band limited. I'm not expecting them to sound good, just thought it would be a project to learn something from.  Any ideas would be appreciated, and thanks for all the information and insights you guys have already put out there!

Short the input or use an appropriate load resistor.  Can’t recall, those are 8 ohm outputs?  Put a 15 minute ohm resistor across it too and see what that does.