I used this board to test a graphics card that was in another computer.
This motherboard was in storage for 2 years
I turned it on, and it booted up, and windows started;
but it was responding with long delays, and i foolishly assumed that it was the operating system.
So went away and came back in 30mins and it was no longer working.
The PSU voltages are all within spec
Prior to storing it, i replaced the input caps with Nichicon HZ, and it was running good with those, right up till i put it in storage.
There is 3.3V on power switch header, but no startup when shorting to ground, and the southbridge doesn't get warm
No dead shorts on the input rail or the CPU VCORE rail;
but there is 30 ohms to ground/earth on VCORE rail, with no CPU installed
Looking at the schematic (attached)...
i removed the 6 VCORE, OST RLX caps, and they all tested within spec and had good ESR.
Removed (and destroyed, when trying to desolder and lift the legs) the low side MOSFETs.
Removed the diode that is in parallel with that rail;
But there is still 30 ohms to ground
From what i can see, the only reasonable path to ground, that is left, is via the driver chip.
Or is it OK for there to be 30 ohms to ground on VCORE rail?
The two MOSFETS and the two diodes, that i striked out in the schematic are not installed on this particular board, so they are irrelevant.
The components that are circled in green are the ones that i removed
Any suggestions or tips on what to do next?
This motherboard was in storage for 2 years
I turned it on, and it booted up, and windows started;
but it was responding with long delays, and i foolishly assumed that it was the operating system.
So went away and came back in 30mins and it was no longer working.
The PSU voltages are all within spec
Prior to storing it, i replaced the input caps with Nichicon HZ, and it was running good with those, right up till i put it in storage.
There is 3.3V on power switch header, but no startup when shorting to ground, and the southbridge doesn't get warm
No dead shorts on the input rail or the CPU VCORE rail;
but there is 30 ohms to ground/earth on VCORE rail, with no CPU installed
Looking at the schematic (attached)...
i removed the 6 VCORE, OST RLX caps, and they all tested within spec and had good ESR.
Removed (and destroyed, when trying to desolder and lift the legs) the low side MOSFETs.
Removed the diode that is in parallel with that rail;
But there is still 30 ohms to ground
From what i can see, the only reasonable path to ground, that is left, is via the driver chip.
Or is it OK for there to be 30 ohms to ground on VCORE rail?
The two MOSFETS and the two diodes, that i striked out in the schematic are not installed on this particular board, so they are irrelevant.
The components that are circled in green are the ones that i removed
Any suggestions or tips on what to do next?
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