Lenovo xiaoxinchao 7000-14 laptop boot failure repair

Lenovo xiaoxinchao 7000-14 laptop boot failure repair
Lenovo Xinchao 7000-14 laptop does not respond to boot, EC reset fault causes no power on, EC program or EC itself damage causes block memory does not run code, boot fault is perfectly repaired.

Machine model: Lenovo Xinchao 7000-14ikb.  
Machine plate No.: 330s_KBL_V09.
Press Switch, no response.
Maintenance process: after receiving the machine plug in adjustable, standby 0.0022, press Switch, no response, decisively dismantle the machine, plate number 330s_KBL_MB_V09.

Lenovo Xinchao 7000-14 laptop boot no response maintenance Figure 1

Xinzao found 15kbl-330s_kbl_Since there is no response according to Switch and the standby is low, check the standby condition and test ec19 pin PM_PWRBTN_R_N did not send out, it should be that the conditions of EC were not met, and + v3p3a was tested_EC VCC_LPC EC_Avcc VCC these are normal, but EC is tested_WRST.

Lenovo Xinchao 7000-14 laptop boot no response maintenance Figure 2

It was found that there was 3.3V at one end of r5510 and only 0.9V at one end. This was not normal. The c5510 was disassembled decisively. Only one was found on the broken board of the mobile phone. After switching on, the standby power was restored to 0.04. After pressing Switch, the current reached 0.49, then to 0.50 and then to 0.30. After testing, all VCC came out, but one signal did not come out.

Lenovo Xinchao 7000-14 laptop boot no response maintenance Figure 3
DGPU_HOLD_Rst ා there is no signal. This signal is sent by the bridge. After receiving nvvddpgood, the bridge will send this signal to reset the display card. The measured nvvddpgood signal has high level, but there is no dgpu_HOLD_Rst ා the high level of this signal, dgpu_HOLD_Rst ා and PLT_Rst phase and PEX generation_GPU_RST#,PEX_GPU_Rst ා and nvvdd_PGOOD phase and GPU generation_Pwrok, but the machine does not currently have PEX_GPU_Rst ා the high-level generation of this signal, so the GPU of the graphics card_The pwrok signal did not come out.

Lenovo Xinchao 7000-14 laptop boot no response maintenance Figure 4
As shown in the figure above, this signal is returned to EC’s 127 pin. Thinking about whether EC is hanging up,SMD REWORK STATION plus tweezers tilts EC’s 127 pin, which is equivalent to converting EC and dgpu_HOLD_Rst ා, then power on, the current finally moves, reaches 0.7, and the screen lights up.

The maintenance is not finished yet. Although it can be started up, Duxian definitely can’t use it. Because this EC is equipped with a program, it happens to have Parts motherboard of this thing. Remove an EC and replace it, and then the above figure is shown.

This is the end of the maintenance. To sum up, the EC reset fault causes no power on, and the EC program or EC itself is broken, which causes the block memory not to run out of code. At this point, the maintenance is over. By the way, the BIOS for me synthesis and modification is attached!