Looks like its a switch mode psu, the large black capacitor will have about 200 to 400vdc across it, as the mains will be rectified by the bridge on the right, then it will feed the oscillator transistor on the heat sink on the right, through the pulse transformer in yellow on the right. The output of the psu is rectified by the two diodes on the other heat sink, voltage feed back regulation is provided by the opto isolator ic (4pin).
start by checking the 400vdc is across the large electrolytic black cap, if so check if there is any outputs from the diodes on the heatsinks across the other black caps, prob 12v or more,depends on the design. the other two pulse transformers are for the back light tubes.