SER 3750H no video, no post, no fan.

ontop01970

So I purchased this second hand, can get it to nothing but the power light turns on for approx 10-12 seconds the back off.

I have reset(cleared) the cmos by using the reset button AND unplugging the battery for an extended time, issue persists.  Swapped out RAM, issue persists.
Different SSD, same thing.  Where could I find a pin-out of the motherbhoard?  In the first image i have attached there is a single 19v connector with nothing plugged in, should there be??
Any help is appreciated

Support-03

Hello there,

From your description, I think there might be something wrong with the motherboard.

But we do not sell motherboard.
Where did you buy this PC ?

ontop01970

purchased it from a friend.  where can I get a motherboard for this?