We are servicing an NEC Electra II. Several times this summer, it has shut-down due to hot temperatures in the room.A fan was installed, and it has been operational for two-months. Yesterday, it shut down partially affecting about half of the phones on the system, but not the T1 card or the analog card. It has two cabinets, and both of the power supplies were functioning. The room was warm because someone had obstructed the fan, and closed the door. We reset the system, and it came back up for now.
My question is, what should be replaced on the system due to the heat exposure?

Thank you,

Rick