C280 power light flashes then goes dead

[Elmo]

Hi All
Wondering if anyone has had this fault on a C280 before
just got a batch of c280 in from the trade and having an issue with one of them
When i switch it on the power led flashes blue the print button flashes orange then goes dead
i have quickly unplugged the hdd and adf and swapped the memory for know good one
no difference tested psu its good any advise would be much appreciated

thanks

[Elmo]

Got it was a broken 5v line from the DCPU to the Print Control Board
cableclip too tight had broken the wire