Solved! amp won't power on

[julzmatt]

Yamaha DSP a590

 

[julzmatt]

Yamaha DSP a590, not switching on

 

[americanaudiophile]

Disconnect all the speakers from the back and try it again. If it turns on then you have a shorted speaker cable or bad speaker. You can reconnect them one at a time to find the bad connection. If it still doesn't turn on then you can download the service manual here
https://www.hifiengine.com/manual_library/yamaha/dsp-a590.shtml
and check if there are any internal fuses that may be blown.
If there are fuses and new ones blow right away don't try it again. You could cause more damage.