Ready NAS Ultra 2 does not turn on

[FirstSon]

I haven't had a NAS in use for about a year. Recently I decided to start it up again. I installed new disks in it and turned it on. Everything worked fine for about an hour. After that, the NAS just shut down.
When I try to turn it on, the power light comes on, the fan starts making noise and after about 10 seconds the NAS just shuts down.
It is also not possible to enter the boot menu. If you press the reset button and turn on the NAS, it also runs for about 10 seconds and then shuts down.
I gave the NAS to an electronics repairman and he says the problem is somewhere on the motherboard. The secondary voltages are trying to go up, the multicontroller is working, there is communication from the RAM to the CPU on the SPD. Most likely some of the capacitance turned into resistance, but to find which one without the controller schematic is very difficult.
Maybe someone has a schematic of the controller for this NAS board or had a similar situation and know how to solve it?

[Sandshark]

Schematics are not available.

[FirstSon]

Okay. Perhaps someone has experienced a similar problem and knows where to look for the answer

[Sandshark]

You can try a different power brick, but iot really doesn't sound like that's it.  I have a Pro2 (same hardware except the processor) with an internal 12V regulator that can only handle spinning up one drive.  I didn't find anything promising to try to fix it. 

[FirstSon]

The repairman used his own, lab-grade power supply with 6 amps. It's not the power supply. There is clearly a short on the board. But without a schematic of the motherboard it is not clear where to look for it

[MCEComputers]

I had similar symptoms with my Ultra 2 a while back, although I never had anyone check voltages or such.

I found it turned off one morning and every time I turned it back on, it would run for about 10-20 seconds and shut back down.

When I opened up the case I found that two of the plastic pins holding the heatsink down on the cpu had snapped so the heatsink was not contacting the cpu. I replaced all four of the plastic hold downs with some 6/32 nylon screws/nuts and that fixed things.

Not sure if this applies to your situation, but it may be worth checking. Overheated cpus can do all kinds of bad things.