Saintsmart Ramps 1.4 dead?

Hey there :-) i just started on working with the electronics for my first printer....havend figured out which but im leaning towards mendel90 ;-)

so i bought me this saintsmart kit [www.amazon.de]

so far lots of problems on burned polou BUT 3 steppers were moving today i want to test further and nothing not one stepper if moving making noise absolutely nothing :-(

im using and psu with 500w when i install die ramps testcode some leds on the ramps bord flash and i can also messure around 0.4v on the polou driver.....

any idea what could be wrong?

best janosch