I have downloaded the manual for your amp. The only other simple mistake you may have made is wrongly setting the balanced/unbalanced input switches for each channel. Your amp does not auto detect and you have to set the switches according to you connection. The XLR connectors are balanced, the RCAs are unbalanced. If these are set incorrectly, then there is no sound. Apart from that, if the power light is on and the wiring is correct, you should have sound.
One other question, do you hear the speaker relays click a little while after turn on? Your amp has to stabilize after turn on, likely because there is a large DC off set for a period of time. A timer circuit then throws the speaker relays, and there is a click. If you are not hearing this click, the timer chip may have failed.
You have to remember the times of the highest rate of failure for a solid state devices is when they are new, after a short period of use.