Looking for a schematic for Siglent SPD3303C

[tkamiya]

I have a Siglent SPD3303C power supply.  Does anyone have circuit diagrams?

Symptoms are, I can set voltage and current but as soon as I push output ON switch, voltage goes to 0.2V.  I am assuming there is a dead short somewhere.  I removed the front PCB from back PCB.  Measure resistance on channel 1 where this symptom appears, it is a dead short.  Channel 2 is 500 ohm or so. 

It's awfully hard to trouble shoot this without a diagram.  Can someone help me?