Lenovo H81M not turning on repair

Lenovo H81M does not turn on, take off the U40, the fault remains, so the target locked C453, take off C453 voltage normal.

Machine model: Lenovo H81M

Fault phenomenon: does not turn on

Repair process: received a Lenovo computer motherboard H81M, placed more than a day can not be turned on, take off the CMOS battery emptied more than a day plugged into the power can be turned on, the failure is a bit rare. In the Xunwei network forum to find BIOS brush on useless. New battery CMOS put on the voltage dropped to 2.7V, replace the D42 after the voltage is normal, the old problem remains.

Continue to look for information on the XUNWEI.com forum, found that there are several responses PCH_DPWROK no voltage common problem, so, download the motherboard drawings, test U40 pin 4 PCH_DPWROK no voltage. A foot only 1.2V, normal 3.3V, take off U40 and then test or 1.2V, target lock C453, take off C453 voltage is normal, 4 feet PCH_DPWROK has a 3.3V voltage. Power on normal, the repair is over here.