Lenovo IB250MH does not trigger repair

Lenovo IB250MH did not trigger, and the fault of the soldered crystal oscillator remained, so a 32.768 crystal oscillator was found from the stock plate, and the waveform was normal after replacement, and the fault was repaired.

Machine model: Lenovo IB250MH

Fault phenomenon: no response when starting up, which means no trigger

Maintenance process: no 3V and 5V standby power supply is available for the machine measurement, the input 12V of the measurement standby chip RT6576 is normal, the linear output 3V and 5V is normal, and there is no standby EN1 and EN2. According to the drawing, EN1 and EN2 are controlled by slp_ Sus # is enabled, so it proves that the standby conditions of the south bridge are not satisfied.

Lenovo IB250MH does not trigger repair Figure 1.

After checking the standby conditions of Nanqiao, RCTRST and SRTCRST were normal. After checking 32.768 crystal oscillator, it was found that there was no waveform. After welding the crystal oscillator, it was found that the startup could be triggered normally, but it could not be triggered after installation. Find a 32.768 crystal oscillator from the material plate. After replacement, the waveform is normal. After repeatedly triggering the startup, it can be started normally. After two hours of testing, it is still normal. So far, the maintenance is over.