Look closely at the red circle in the middle of this picture - you can see a beefy ground trace going into the 19 pin of the RS232 level translator. This was pulling the active low FORCEOFF signal to ground, which had been permanently disabling our transmission to the printer. Jared had to cut the 19 pin off of the IC and solder a flywire between the 19 and 17 pin, which was already wired to power. After that fix, the printer worked perfectly.