The first thing the 35P attempts to do when first powered on is synchronize with the printing mechanism. If the printer is jammed the chronograph will not power on. Test this by turning DIP switch #7 to the OFF position to disable the printer. Restart the chronograph by plugging in a Skyscreen and check the LCD display. If the display reads “- – -0” you will need to un-jam or replace the printer. If the display is still blank with switch #7 in OFF position, replace the battery and check battery leads for broken connection.