Optoma HIGH-END - Manual (Page 60)

Appendices
58
 RS232 connection fail:
 Replacing the lamp:
Remote Control Problems
If the remote control does not work
 Check the operating angle for the remote control is approximately
±22.5°.
 Make sure there are not any obstructions between the remote
control and the HD81-LV’s Box. Move to within 6m (20ft) of the
HD81-LV’s Box.
 Make sure batteries are inserted correctly.
 Make sure batteries are exhausted. If so, replace weak batteries in
the remote control.
 Projector side
don’t have IR receiver.
IR receivers are only
on front of Box side
and IR Module.