Help Chiro C-802, volume too small.....

I Bought a used Chiro C-802 with AC3, DTS & Tuner built in. I hooked it to Threshold S/1000, 500 watts mono power amps & ATI 1506 bridged for 3ch/450 watts with Genesis APM1 & 750 speaker system. But C802 produces a very little sound level on all source. Please see the comparison between Mcintosh C-39 & Chiro C-802. Both have digital display scale 1 to 99.

At level 10,
C39, decent, comfortable sound / C802, no sound.

At level 20,
C39, somewhat loud, comfortable sound / C802, no sound.

At level 30,
C39, almost too loud sound / C802, very little sound.

C802 has to be driven to over 80 for good comfortable sound.
I never tried to drive C39 to over 40 cuz it's too loud.

Please help.