QNAP TS 253A dead motherboard - need help with diagnosis

Hi All,

I seek your help on a QNAP TS 253A (network attached storage) motherboard.

I bought this device broken, so I don’t have much history on it. The problem is simple: it will not turn on. No LED’s, no nothing.

I have disassembled it hoping it would be a simple fix, but I lucked out and I’m running out of ideas.

Here’s what I have done/determined thus far:

1. 3.3v, 5v and 12v rails are alive. (external PSU provides the 12v)
2. The board is pulling 0.25-0.26 amps
3. The caps (buck converters) above the CPU (green box in the pic) are measuring 1v.
4. I have removed the bios battery thinking it could be a frozen bios, but no
5. I noticed one of the two ethernet chips (intel i210) was steaming hot, so I have removed it from the board. This is highlighted with a red rectangle on the back side of the board.
6. When I plug the ethernet cable in, the yellow network LED comes on
7. Prior to removing the ethernet chip I think I felt the CPU getting warm on a couple occasions
8. One of the buck converters (red rectangle on front of board) does not appear to be outputting anything (could this be the 1.5v for the RAM?)

What I am considering doing:

1. Replacing the ethernet chip, because maybe the Super IO (ITE it8528e) needs a signal from both ethernet chips?
2. Replacing the Super IO
3. Injecting a few amps into the dormant buck converter to see if there’s a short

Front pic:

Back pic:

Any help is appreciated.

Thanks a bunch!