I have an Alienware 17 R3 (board is a C912P) that I recently starting trying to repair. Originally the issue was the charger going into protection mode when plugged in to the laptop. I found a short on the motherboard (one of the capacitors on the back of the board under the DRMOSes for the CPU) and the charger when plugged in now doesn't go into protection mode anymore. The laptop powers on, the lights on the keyboard, alien head, and alienware logo light up, and the fans spin. The issues are:
1) The battery doesn't charge. I've probed the charger jack and it's only receiving 0.633v when in my experience it should be getting much more voltage going through to the battery. The alien head should also light up when the battery is charging and it doesn't even though I've made sure that all the ribbon cables are attached properly.
2) The board doesn't stay on for more than 5 seconds. It will power on, the keyboard lights up along with the Alienware logo. The alien head will light up after 4 seconds but almost instantly after that it will shut off and restart, and the cycle repeats. No video signal is ever displayed and the speakers (plugged in) don't give a beep code and no color code on the alien head is ever displayed.
3) With the heatsink either on or off, I cannot feel the CPU, GPU, nor the PCH getting hot when normally they should be getting warm just from booting.
I've probed around the board and I am getting the main 19v rail. I am also getting 3.3v and 5v. The coils above the CPU are measuring 3 ohms on both sides. The coils next to the DCIN Jack are also showing the correct voltages. I've also measured the capacitors on top of the PCH chip and they're getting 3.3v as well. I've checked the BIOS chips on pins 1 and 8 and they're getting the correct voltage and not showing a short to ground, except on pin 4 where it is connected to ground. I've also checked that the CMOS battery is good and tried clearing the CMOS. No changes.
Problem also occurs whether the RAM is seated, only 1 stick, both sticks, or none at all.
With the above being said, I don't know where to go next in diagnosing what the actual issue is. I've gotten a step farther in getting it to at least power on. Now I want to see if I can make it actually function.
I do have a board diagram and schematic.
1) The battery doesn't charge. I've probed the charger jack and it's only receiving 0.633v when in my experience it should be getting much more voltage going through to the battery. The alien head should also light up when the battery is charging and it doesn't even though I've made sure that all the ribbon cables are attached properly.
2) The board doesn't stay on for more than 5 seconds. It will power on, the keyboard lights up along with the Alienware logo. The alien head will light up after 4 seconds but almost instantly after that it will shut off and restart, and the cycle repeats. No video signal is ever displayed and the speakers (plugged in) don't give a beep code and no color code on the alien head is ever displayed.
3) With the heatsink either on or off, I cannot feel the CPU, GPU, nor the PCH getting hot when normally they should be getting warm just from booting.
I've probed around the board and I am getting the main 19v rail. I am also getting 3.3v and 5v. The coils above the CPU are measuring 3 ohms on both sides. The coils next to the DCIN Jack are also showing the correct voltages. I've also measured the capacitors on top of the PCH chip and they're getting 3.3v as well. I've checked the BIOS chips on pins 1 and 8 and they're getting the correct voltage and not showing a short to ground, except on pin 4 where it is connected to ground. I've also checked that the CMOS battery is good and tried clearing the CMOS. No changes.
Problem also occurs whether the RAM is seated, only 1 stick, both sticks, or none at all.
With the above being said, I don't know where to go next in diagnosing what the actual issue is. I've gotten a step farther in getting it to at least power on. Now I want to see if I can make it actually function.
I do have a board diagram and schematic.
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