Acer AL17171 monitor not powering on

[varunme]

My Acer Al1717 monitor not powering on, i replaced all capacitors in the power section including the big 100uF/400V one, still not powering on, None of the power rails are giving correct voltage

checked the optocoupler, transformer and others, but no problem there,
what can be the actual problem ?

 

[pradeep.g.belchada]

first check 300vdc on 100mfd/400v cap

 

[varunme]

yes, 300Vdc is there, but across the rectifier bridge no voltage (Input and output)