Konica Minolta magicolor 1690MF - Manual (Page 269)

Duplex Option 10-10
2
Remove the tape affixed to the
rear cover.
3
If the locking pins are installed on the left and right side at the back of
Tray 2, remove them.
To remove a locking pin, turn it to either the left or the right so that its grip
is vertical, and then pull out the locking pin to remove it.
4
Prepare the duplex option.