Asus P8B75-M LX Plus motherboard no booting repair

Main board model: ASUS P8B75-M LX Plus

Fault phenomenon: main board no booting

Maintenance process:

A p8b75-mlx Plus fault motherboard, on the test card, sometimes it shows E9, sometimes shows 00 does not drop the line.

Asus P8B75-M LX Plus motherboard no booting repair Figure 1.
Test all VCC, except for CPU VCC and set display VCC, everything is normal. The CPU VCC chip is UP1625P, the 5th pin is on, measure VCC 0V, connect to PQ80, measure 1 pin as high as 1.05V, measure 3 pin connected to PQ81, and measure 1 pin of PQ81 as 1.05V. PQ81 normally should lower VCC of 3 pin, and judge PQ81 damaged.

Asus P8B75-M LX Plus motherboard no booting repair Figure 2.

Asus P8B75-M LX Plus motherboard no booting repair Figure 3.
After replacing PQ81, turn on the running code card 69.

Asus P8B75-M LX Plus motherboard no booting repair Figure 4.
Observing the whole board, it is found that Repeat welding and dual BIOS have moved on the bridge.

Asus P8B75-M LX Plus motherboard no booting repair Figure 5.
Official website found the latest BIOS brush on the left (by PCIE). After brushing the boot code,booting up is normal. Put it back on the motherboard and boot it. After copying the machine for one hour, there is no problem, and the maintenance is over.