Master Out can't be set at 15. It's max level is 0dB.
Very likely your amp SEND is not sending enough juice to the Eclipse input. You need to boost Eclipse input level to fill its headroom properly. Keep Master Out on 0dB and set IN GAIN @ +7 or +8 dB..or even flat out. This should help to lite up those input leds and help with the tuner and any other pitch detection algorithm, as these requires a proper input level.
all the best