NAD C270 amp won't switch from red power/protection to green.

https://elektrotanya.com/nad_c370_sm.pdf/download.html

https://music-electronics-forum.com/forum/amplification/other-amps/920148-nad-c-370-no-sound-from-speaker-outputs#post920172

https://audiokarma.org/forums/index.php?threads/nad-c370-repair.916194/

Sometimes you can find the faulty part by touching the parts inside the amp. Only touch the plastic parts not any metal parts! As it is on one channel you have a good channel to compare the bad. Often small transitors can become noisy so start with them!

Hello
Check the connection to speaker with this amp, for any short or any other fault. disconnect the outputs, ie, speakers from the amp, and switch it On, and see the protect display comes or not. If it comes, the fault is internal and the set need service.
Your M3 dual Mono integrated amp, is of high output power and its outputs are protected against any overload or short circuit. If the system detect any among this condition specified above, it will show protect mode display.
Never load this amp, as protection display is there, as it may damage the speaker or its internal power amplifier section circuits, may cause more money to get it repaired. OK.

3 blinks indicates lamp door is not on or has not been reinstalled properly. This also could mean the lamp door switch has failed itself. Try removing the lamp door and putting back on, if that doesnt correct the problem then I recommend having the switch replaced.

The flasher does not stop the brake lights from working. Check # 18 fuse in fusebox under lower left side of dash. if it's ok, the brake light switch, on the brake pedal arm is next. light green wire with red stripe is hot if fuse 18 is ok. Depress brake pedal, light green with no stripe should have power. if not, replace brake light switch. If light green wire has power with pedal depressed, combination switch under the steering is next. Remove the cover from around the combo switch {under the steering wheel}. depress brake pedal, light green wire should have power. If it does, pedal still depressed, orange with light blue wire & wire with light green & orange should have power. Those 2 wires are brake & rear turn signal wires. { The turn signal switch should be in the middle, not right position or left. while checking for power in the last 2 wires. Good Luck drvolt.

See link below.

http://www.pithed.org/2007/10/12/nad-c370-protection-circuit-repair-amp-fails-goes-into-protection-mode/

You likely have damaged one side of the amplifier. SOME amps can stand to be shorted, but many will pop one or more transistors. Time for service in the shop I am afraid.

My kicker amp zx1500.1 keep going in protection mode I unhooked the sub speak wires and put the ACR cords back in and it didn't go in protection mode what next

Change resistors 333 & 334 - 47k-1W

I suggest rechecking the speaker wiring in case there is a small "whisker" of wire touching either the case or adjacent terminal, also check the speaker end of the wires for same. Do you have a pet? I have seen wires chewed partly through by cats (& rabbits)! See the information from the manual below: http://207.228.230.231/manual/NAD-C370.pdf