Hello,
This laptop had a short on the main power rail, which I was able to trace to a shorted high side of the dual N-channel mosfet, PQ23, highlighted in Yellow on the attached picture. I believe this is the VRAM power supply. I also removed the mosfet above, PQ26, just so I could test out of circuit. It is OK. With the mosfets removed, the main power rail is no longer shorted.
Checking further, all the GPU coils are reading 0Ω resistance to ground, so this probably means the GPU is dead. The two coils alongside the shorted mosfet, CHOKE11 and CHOKE13 read 20.6Ω to ground, which may also indicate VRAM damage.
There is an empty coil location on the board (Blue arrow). Would this be a suitable point to carry out a short circuit test?
Motherboard number is MS-15421 Rev 1.0

This laptop had a short on the main power rail, which I was able to trace to a shorted high side of the dual N-channel mosfet, PQ23, highlighted in Yellow on the attached picture. I believe this is the VRAM power supply. I also removed the mosfet above, PQ26, just so I could test out of circuit. It is OK. With the mosfets removed, the main power rail is no longer shorted.
Checking further, all the GPU coils are reading 0Ω resistance to ground, so this probably means the GPU is dead. The two coils alongside the shorted mosfet, CHOKE11 and CHOKE13 read 20.6Ω to ground, which may also indicate VRAM damage.
There is an empty coil location on the board (Blue arrow). Would this be a suitable point to carry out a short circuit test?
Motherboard number is MS-15421 Rev 1.0
