For the past few months, my 2018 MXR has been intermitted black screen dead (no sound or noise from bike) when key is turned to On position. I suspected the 9 Volt to be the culprit. I successfully replaced the 9 volt battery last night and it has appeared to solve the key On problem. I have read many posts that the original 9 volt battery was the Energizer Advanced Lithium. When I opened by ACM last night, my battery was an Energizer Ultimate Lithium. Fortunately, the Energizer Ultimate Lithium is easy to find at many stores. Also, I was able to maneuver the ACM and get the access cover removed (it definitely tried my patience) to replace the 9 volt without pulling the main battery and disconnecting all the other stuff.