C5235 won't power on

[repeatcopiers]

We have a C5235 in the field that about 5 months ago, customer called with No Power. Tech found that the fan under the Main #1 was running, there was 1 light lit on Main #1, you could hear a clicking noise, the fan would stop, then the clicking noise again and fan would come back on but nothing else. Process of elimination, Main Controller #2 was replaced and problem solved. Fast forward to today, the exact same thing is happening. What could be killing these Main Controller #2?

[Phil B.]

We have a C5235 in the field that about 5 months ago, customer called with No Power. Tech found that the fan under the Main #1 was running, there was 1 light lit on Main #1, you could hear a clicking noise, the fan would stop, then the clicking noise again and fan would come back on but nothing else. Process of elimination, Main Controller #2 was replaced and problem solved. Fast forward to today, the exact same thing is happening. What could be killing these Main Controller #2?

power surge coming over the EtherNet port?