The MA68II requires the battery to do a measurement. The battery pack must have a minimum charge. The power adapter alone does not provide enough current to run the unit. Be sure to check to see if the battery pack is installed and fully charged. A fully charged battery pack will provide enough current to run the instrument without the power adapter connected.
REPLACING THE BATTERY PACK
1. Unplug the AC adapter and click power switch to OFF. 2. Carefully set instrument on its top and slide battery access cover toward rear of instrument and remove. 3. Grasp plastic tab that extends from battery pack and pull until pack is removed. 4. Slide new—or charged—battery pack into instrument until connector is properly seated. 5. Reinstall battery access cover by sliding into position. 6. Discharged battery packs should be charged in the instrument for 16 hours.