Here is the working solution to OBDSTAR X300 Classic G3/Key Master Classic G3 not turning on problem.
Detect and Repair OBDSTAR G3:
Step 1: Remove the rubber case. Then loosen and remove the fixed hex screws driver using a screwdriver.
Step 2: Open the back cover and press down on the battery connector clip with your hand, then pull out the battery connector.
Step 3: Use a multimeter set to the ohms range to test the two ends of capacitor C75. If the resistance is around 0Ω, it indicates that U17 and L8 are damaged and causing a short circuit. Replace U17 and L8.
Step 4: Use a soldering iron or hot air gun with the temperature set to 350 ±10°C to desolder and remove U17 and L8. (Replace L8 with a 1uH inductor.)
Step 5: After the replacement, use the multimeter set to the ohms range to test the two ends of capacitor C75 again. If the resistance is approximately 1.36KΩ, it confirms that U17 and L8 have been successfully replaced.
Step 6: Insert the battery connector, reassemble the back cover, and press the power button to turn on the device. If it starts up normally, the replacement is successful.
Step 7: Use a screwdriver to fasten the screws to the back cover, and put the rubber case back on. The replacement is complete.
Turn on OBDSTAR G3 device again.
