Today, we are repairing a MacBook Pro. Model A1502. Connect to power. No response. Light is off. See the meter on the power supply. First, a visual inspection. See the bottom case. Cockroaches. All the bits here. Roaches. Cockroaches likely caused the power issue. Unplug the battery. Peel the sticker off. The motherboard. Look for liquid damage. Many cockroaches here. Everywhere. And the Liquid Contact Indicator is red. That means liquids or cockroaches have infiltrated the motherboard. Check the other side. More cockroaches here. No significant corrosion detected. Connect to power. To check power issues. Try with just the motherboard. With motherboard only, there is no current or light. The readings show no change. Remove the hard drive. Motherboard part number is 820-4924-A. Serial number here. CPU and memory size. Open schematic and board drawings. Let’s check the main power bus PP3V42_G3_REG. This one here. PP3V42_G3H_REG controls the green light circuit. Check if voltage is produced here. L7095. This inductor is on the other side. This is the inductor. Check its resistance to ground with our multimeter. Set to ohms. Diode mode. Resistance is normal at 304 Ω. Ground resistance is normal. Connect to power. Test the inductor for voltage. The inductor has no voltage. Trace the inductor’s voltage to check the circuit. Have a look at this chip. What U7090 needs. First, power supply from pin 6. Here, through these diodes to here. Check pin 6 on U7090 for power. Test for voltage. No voltage on pin 6. Let’s try pin 1 on D7005. See if pin 1 has voltage. No voltage. Investigate further along. There is no voltage at D7005. Try further up the circuit. On top, the fuse F7005. Here’s the power source connector J7000. Power goes through the fuse. Then forks into two routes. One leads here to power a chip. The other leads to the charging chip. Good. Now locate F7005. Over here, test this inductor. Inductors have power on both sides. Inductors conduct electricity. After the inductor, a certain Q7010. Check this MOSFET Q7010. Pin 1 for voltage. Here is Q7010, the transistor. Test shows no voltage. This means voltage does not reach here. Power is lost after the transistor Q7010. Now look at pin 4. Test Q7010’s gate for voltage. Pin 4 is 17.38 V. This is a p-channel MOSFET. Pin 4 must pulled to ground for current to flow. So we have a problem here. Have a look under a microscope. We can clearly see the Q7010 I was measuring earlier . And beside it, a corroded resistor. This chip and pin are also corroded. The resistor and chip are all corroded. First, let’s replace the resistor. Here it is, R7011. R7011. When power reaches here, it is cut. Causing voltage to go over 17.0 V. 17.0 V because it was not split. After changing the resistor, connect to power. Light still does not show. No change in current. There are other problems. Now, let’s check if voltage goes through the resistors and getting split. Check if there are problems with the pins. Over here is resistor R7010. Find pin 1 and 2. It is 17.4 V. Look at this diode. This diode connects to ground and the resistors,
to R7011. Maybe the diode is faulty. Because pins 1 & 2 have the same voltage. Normally, this diode drains to ground to give 6.8 V here. This diode regulates voltage. Try changing the diode. Both pads show no voltage. Connect power after changing the diode. The light comes on. Current has started flowing. R7011 goes to Q7010’s gate. Voltage at pin 4 is 6.8 V. That is normal. Test the voltage again. It should be 6.8 V. It is normal. Test voltage at the inductor again. 3.43 V. It is normal. Good. Put everything back together.