When It comes to electrical "tools" it does not hurt to check it your self. IMO I get a to thinking its electrical which means there is no error. I had to check out some electriclal components some of them 110 v I could not figure out the problem. After about 4-6 hours of troubleshooting i found that the problem was with my digital volt meter. I ran down the street and bought a new one and checked both side by side . The new one had the correct readings and the other new one had false reading across the board...... So as with anything else it does not hurt to check its accuracy from time to time......