Yamaha EMX7 powers on then off

[nosaj]

This was a music store dumpster dive. i realize it may be out of my league here . But I'd like to see if I could turn this into a learning experience.
It powers on then shuts off. I realize it could be the SMPS or it could be shorted outputs. Is this they type of amp i could disconnect the output section?
If not maybe I could construct a load to test the SMPS?
nosaj

[The Dude]

I've repaired a couple of those, and recall finding open resistors in the SMPS. I don't remember which resistors, but do remember that both units had the same failure. That said, often when an SMPS starts and then shuts down, it's because something is shorted on a secondary supply, so I'd check resistance from secondary supplies to ground to see if any of the supplies are shorted. Then trace from there. I've often found shorted diodes on secondary SMPS supplies. As I said, it's been a while since I worked on one of these, but I also remember chasing my tail for a while after the repair and finding the thing still not working. I discovered that grounds are carried via assembly (shields, etc.), so it's necessary to run ground jumpers between boards when you have it disassembled, or it won't run.

[nosaj]

Well got to it. Found that disconnection cn201 which sends -+15 and +-5v to the power board allowed the machine to boot up. So the issue will be on those rails on the power amp I presume.
Definitely a different beast here tat what i am used to seeing.
nosaj