Canon C2030 - Remove the paper from the output tray

[GGM]

Hi - picked up a second hand Canon C2030.
The unit is in great shape but throws the error: Remove the paper from the output tray.
There's no paper in the output tray and the little flap moves freely.
I've read some posts about similar errors coming up when finishing units are removed. Unfortunately, I don't know the history of this machine except the that donor says it was working before it was shut down.
Can anyone point me to a solution?
Thanx!

[Tricky]

Re: Canon C2030 - Remove the paper from the output tray

Is the sensor missing from where the duplex output part, above the paper tray.

[Brian8506]

Re: Canon C2030 - Remove the paper from the output tray

I believe when there is no finisher there should be 2 flags. One for exit detection and one for the tray being full.