We have a dell 5210N printer at work that needs fixing.
At random times it shuts off and there are 5 beeps coming from the mainboard. Printer is completely inoperable at that point.
Closing the media tray with force will make it work again, but it will go to above mentioned problem state again.
Dell support hasn't seen this before.
Is it happening at a particular time or when something is happening?(printing, other devices powered on) It might have to do with it being in a surge protector or battery backup and it not getting sufficient power.
Otherwise it sounds like one of the boards or the wiring has gone bad. If you have a background in electronics, you might try reseating the cables on the power boards and the controller card, but otherwise I would write it off as not worth repairing.