XEROX D110 Won't boot up

[Fairandsquare]

It will power up the fuser and it seems to start doing system checks but the dislay stops on page 1/6 and will stay like that. I've shut down, re-started, unplugged and restarted, checked the power. At a loss.

[Milo Wilson]

Check the front door interlock switch.

[xcopytech]

Start long boot diag mode to see will you get any error code.
Check memory on ESS PWB and if still same replace ESS PWB

[Fairandsquare]

Check the front door interlock switch.

Interlock is working
nothing happens if door is ajar

[Fairandsquare]

Start long boot diag mode to see will you get any error code.
Check memory on ESS PWB and if still same replace ESS PWB

Very much a novice. Can you provide a procedure?