Rigol DS1102e partially powers on. Help please

[Vetteguy112233]

Last year I purchased the unit at a local yard sale and the user couldn't remember if it worked or not but upon getting it home and trying to Power It Up I found that it sometimes will show the green lights on the switches but almost immediately they go out. Every once in awhile the screen will also turn on with a white color but also immediately turns off and goes black however it appears the screen is still on but just showing a black color. I can also hear the fan running and right before things shut off the relay underneath input Port 1 clicks but I've been told that's normal. I guess that's what I get for $20

It's currently torn apart on my bed and I don't see any leaking or bulging caps, charred areas or any other signs of an obvious problem.

I'm still learning and would love to fix this device which will obviously Aid me in fixing others once I learn how to use it

[Psi]

Put a meter on each supply rail on the power supply PCB and see if one is disappearing when the thing shuts off, could be a sign of a problem where the PSU is shutting-down or one rail is disappearing .
Also check the psu board power on wire (if it has one) to see if the control board is commanding a turn off or not.

WATCH OUT FOR MAINS VOLTAGES on the PSU board.