I would like to use blender PSU board. 
To power motor of the blender. Whole blender consists of this this board, control board (which blew up) and motor itself. I am now trying to hack this board to output power and use arduino (with some mosfets) instead of control board.
I know this is some kind of AC to DC converter (the motor itself is DC, I powered it with my Lab bench power supply and it spinned). I tried to trace all connections with multimeter and found datasheet (LNK362-364) for chip between diodes (left bottom on the picture). All I was able to get was a DC voltage jumping from 2V to 30V, measured from LNK's pins (pin 5 and 7). I imagine that is rectified sine wave (but I don't have oscilloscope to prove it). I wasn't able to get stable DC from this board, I guess I have to plug somewhere around these caps, but where to get reference point? There is transistor under the white goo, I guess it could serve a safety feature for the board.
The pins on the top was where the control board was connected. I tried to measure, connect them, but with no luck. I am kinda lost now, where should I go next, to obtain power from this little device.
One more photo from the back:
Best Answer
Unless you are comfortable with and competent to work with AC Mains power that is NOT isolated, you probably should not attempt this project.
The clue that this is dangerous is the blue and brown wires on the right-side of the board. This board is powered directly from the AC Mains and there is NO isolation from the mains.
All that said: if you want to proceed, you need to do some work.
The very first thing to do is to trace the board out and create a schematic diagram showing all of the parts on the board and how they are connected together. Modify your question by adding the schematic that you created.
Only then can anyone else provide meaningful advice.