The machine malfunction after thunderstorms. Remove the power supply board, found that F1 burned black, varistor TNR1 fire crack, explains the fault is really caused by lightning strike. Measuring resistance is close to zero on both ends of the C5, online examination Q1, Q2, Q3 have short circuit breakdown, remove the damaged components after replacement, plug test, machine failure remains, but has not burn insurance tube F1. Check carefully, and found that Q1 S limit the R20 flow resistance has been open. Change after the reboot, troubleshooting. Fax while using the pressure sensitive resistance for protection, but encountered strong thunderstorm weather, users better unplug the power plug, in order to prevent lightning caused unnecessary loss.j39service manual download site