Path to PS_HOLD: A Hidden Culprit in No Power Repairs
In the realm of mobile phone repair, the dreaded “No Power” issue can be a daunting adversary. While the usual suspects like battery, charging port, and display often take center stage, there lurks a more subtle culprit: the PS_HOLD path. This article delves into a real-life case where a seemingly simple “No Power” on a Mi 11 phone was traced back to a faulty resistor on the PS_HOLD path, leading to a successful repair.
The Case of the Missing Power:
The journey began with a Mi 11 suffering from a complete power outage. Initial troubleshooting ruled out common culprits like a faulty battery or charging port. With the phone disassembled, the focus shifted to the motherboard.
Amp Check and CPU Reassembly:
A low amp draw of 45mA when pressing the power key indicated no short circuit. However, the amp reading during charging, a shaky 0.2A, raised concerns. Upon closer inspection, a component near an IC was found boiling, leading to the suspicion of a faulty capacitor.
The Broken Resistor and the PS_HOLD Path:
Further investigation revealed a broken resistor, R3102, connected to the PMK8350 IC, a clock generator. This resistor, with a value of 1K ohm, resided on the PS_HOLD path, crucial for holding the power supply stable. Replacing the resistor instantly brought the charging amp down to a reassuring 0.1A.
The Importance of Checking PS_HOLD:
This case highlights the often-overlooked role of the PS_HOLD path in “No Power” scenarios. While components like the Power IC, CPU, and RAM are rightfully prioritized, neglecting the clock generator and its associated paths can lead to missed diagnoses.
More Than Just Mi 11:
The PMK8350, along with its neighboring 38.4MHz crystal and PHONE_ON_N path, is not exclusive to the Mi 11. These components play a vital role in other phones like the Redmi Note 11 Pro 5G and Samsung A73 5G. Therefore, checking the PS_HOLD path and clock generator circuits should be a routine part of troubleshooting “No Power” issues in various phone models.
A Lesson in Perseverance:
This repair serves as a reminder that even seemingly straightforward cases can harbor hidden complexities. By meticulously tracing circuits, identifying faulty components like the resistor, and understanding the importance of less-obvious paths like PS_HOLD, technicians can conquer even the most challenging “No Power” situations.
With a lot of goodwill, we can all conquer the power of “No Power”!