Here is a video demonstrating how to use the Blinder test mode to check your heads. I shot this video of my M40 when it had a head develop a water leak, allowing water to ruin the head after a freeze. Please note that you must have a camcorder or cell phone to see the heads firing back when you shoot it with the remote.
[ame=http://www.youtube.com/watch?v=o3Be7l5StAk]YouTube - Blinder M40 test mode demo[/ame]
Bookmarks