I have a B85 Gaming board here with fancy extruded dragon heatsinks, so the guy i got it off was running a gaming I7 not sure if its a K model or not? but its possible there was some overclocking going on.
Symptoms:
Things ive tried:
Removed and flashed bios chip with latest MSI bios.
So It would be handy if anyone here had schematics for this board, but if not I might start with looking at the datasheets for the mosfet drivers on the Vcore. I would like to know exactly why they would not be activating the mosfets gates and whether or not some kind of short circuit protection is in place. Or even see try to see if the drivers themselves have failed.
Please let me know if there is anything that i may have missed?
Symptoms:
- With GPU and ram inserted, board can start up and stay on, I have a Post Card here TP611 or whatever and it reads 0.0 the whole time no post codes. from standby to on there is no change in LEDS, just PCIRST which is always on.
- Probing around in ON state I can see Most voltages are present, 3.3v, 5v, 1.5v PCH is receiving its 3.3vSb and 1.06V on the core voltage, slightly warm to the touch.
- No substantial Vcore voltages,
- CPU_IO reads 0v,
- CPU_CORE3 0.7v,
- CPU_CORE2 0.6v
- CPU_CORE1 0V
- CPU_VCOMP 0V
- CPU_VCCIN 0v
- CPU_VCCIO also 0V
- Probing around on the mosfets show a steady 12v on the high side of the mosfet with 0v on the drain, this suggests that they are not being activated by the driver?
- I also probed around for resistance with the CPU removed, 100-200kohm on some points of the mosfet im guessing the 12v rail and about 3-5kohm on the other side which is probably the VCORE side. No obvious looking shorts.
Things ive tried:
Removed and flashed bios chip with latest MSI bios.
So It would be handy if anyone here had schematics for this board, but if not I might start with looking at the datasheets for the mosfet drivers on the Vcore. I would like to know exactly why they would not be activating the mosfets gates and whether or not some kind of short circuit protection is in place. Or even see try to see if the drivers themselves have failed.
Please let me know if there is anything that i may have missed?
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