Mx850 remote stopped working. replaced batterries no display still.

maybe there is no response on the other side, try to send fax to another number

Check the remote control for its infrared emission. Check it with fresh batteries. Check it by pressing all the keys. You can detect the presence of infra-red emission from the remote control, using a cell-phone camera. If you wish to get more details about how to check a remote control, please visit this site. One among the posts has details about it. In some cases, the remote control might need to clean.
http://electronicshelponline.blogspot.com/
http://remotesearch.blogspot.com/
Search the site by type in this key phrase "how to test a remote control "in the "search box at the top right of the display window of the Homepage" to get the related post quickly.
https://youtu.be/wUpnETSm6_k
https://www.youtube.com/watch?v=jsSCNCW3IbQ [open and clean]
https://www.youtube.com/watch?v=Qp-l1uh-5gE [open and clean]

Replace the button or the plates beneath them

open your remote and look if you dont have a bad soldering some where use a good magnifier
if all look good its could be the ir led blow or the
xtal frequency controler.it as to be some ting like that
hope that will help ;sometime the batterry look full or test over 1.5 but theres not good replaced before to be shure..
have a nice day

Take off your batterry open your remote control, there are 4 phillips screw at the back, you will see a brown circuit board take that off ,on the other side of the circuit board, (one that is painted green) clean that surface with a piece of cotton slightly wet with a rubbing alcohol, and clean the black carbon thingy on your remote pad as well, make sure that they're both dry, then replace your remote with a new battery this'll work

Performing Maintenance:




Note :
Be sure to install the ink tanks in the correct order indicated by the label on the Print Head Holder. The machine will not print if an ink tank is installed in the incorrect position.
Step 1
Printing the Nozzle Check Pattern.




If lines are missing or if white streaks appear


Step 2
Print Head Cleaning.

If the problem is not resolved after performing Print Head Cleaning twice


After cleaning the Print Head, print and examine the nozzle check pattern (Step 1) again.


Step 3
Print Head Deep Cleaning.



If Print Head Deep Cleaning does not resolve the problem, turn off the machine and perform another Print Head Deep Cleaning after 24 hours. If the problem is still not resolved and if you are sure that the ink didn't run out, then the Print Head may be damaged. Contact your Canon service representative.

Hope this helps.
All the best.

glshultz,
I am having the same problem with the same remote. Were you ever able to solve the problem? If so, how? Any help is much appreciated.

Possible scenarios:
Out of battery:
Solution:
Replace batterries

Connection has been intercepted:
Solution:
Take the back off of the remote and then go to the Wii and open the little compartment left of the Wii. Then press the red button on the Wii remote and console simultaneously untill something happens like, connection restored on the Wii screen.

Replace the batteries from the remote control. Press and hold the TV button on remote for 5 seconds. If the red light shines bright, your remote is OK since it is showing it's programmable side. If unit still won't go on using the remote, reboot the whole system by unplugging the power cord and other wire from the Subwoofer. Wait one minute, then replug all and see if the system displays BOSE 321 in front when re-connected. If so, try the remote and if that doesn't work, your dead, the Infra red communication device from the unit to the remote is busted inside the unit and needs to be returned to the company like mine!!!!!