🔧 Introduction
If your Infinix Hot 10 Play (X688) shows charging indication but the battery percentage is not increasing, or charging behaves abnormally, this guide will help you diagnose and fix the issue.
This is a real hardware-level repair case, especially useful for:
- Mobile technicians
- Beginners in chip-level repairing
- Advanced hardware learners
⚠️ Problem Symptoms
During testing, the device showed the following issues:
📱When Mobile is OFF
- Charging symbol appears ✔️
- Battery percentage visible ✔️
- Current consumption: ~40mA only ❌
- Battery percentage not increasing ❌
📱 When Mobile is ON
- No charging symbol ❌
- Current consumption remains ~40mA ❌
- Device not charging at all ❌ .
🔍 Diagnosis Process
After detailed hardware diagnosis:
- Checked charging current → Abnormally low
- Checked charging IC input signals
- Found abnormal voltage at VCDT line
📊 Key Observation
- Measured VCDT voltage = 0.8V ❌
- Expected VCDT voltage ≈ 0.53V ✔️
👉 This confirmed a fault in the voltage divider circuit
⚙️ Circuit Explanation (Important for Learning)
The VCDT line is connected to the PMIC (Power Management IC)
👉 IC Used: MT6357CRV PMIC
This line uses a voltage divider circuit:
- Input Voltage (Vin) = VBUS (5V from charger)
- Resistors used:
330KΩ (R1)
39KΩ (R2)
👉 Learn more here:
Resistor as Voltage Divider – Complete Explanation
📐 Formula
Vout = Vin × (R2 / (R1 + R2))
👉 This generates a safe reference voltage (~0.53V) for the PMIC to detect charger presence.
❗ Root Cause
The 330KΩ resistor value had decreased ❌
This caused:
- Increase in VCDT voltage (0.8V instead of 0.53V)
- PMIC misreading charger input
- Charging failure
🛠️ Solution (Step-by-Step Repair)
- Locate the VCDT voltage divider circuit
- Measure both resistors: 330KΩ resistor ❌ (faulty) 39KΩ resistor ✔️ (normal)
- Replace the faulty 330KΩ resistor
- Recheck voltage:
VCDT restored to ~0.53V ✔️ - Test charging:
Charging current increased ✔️
Battery percentage increasing ✔️
Charging symbol restored ✔️
✅ Final Result
After replacing the faulty resistor:
- Device charging normally ✔️
- Proper current consumption restored ✔️
- Charging indication working correctly
🎥 Watch Full Repair Video
👉 You can watch the complete repair process here:
Watch on YouTube
📌 Conclusion
This case highlights the importance of:
- Checking reference voltages (like VCDT)
- Understanding voltage divider circuits
- Measuring resistor values accurately
👉 Even a small change in resistor value can cause major charging issues.