smiba
New member
[SOLVED][820-3023] ~0.5s fan spin on loop - Keeps power cycling - CPUIMVP_TON keeps going low
Hey everyone
Going on a nice vacation in a few days, just want to finish this last laptop before I close off and enjoy a break
Laptop has been touched by idiots before, but no signs of soldering or ultrasonic. But they managed to pull off the screw holder for the SSD (How even? You'd have to pull really hard). No short on the surrounding pads and the damage is right now mostly cosmetical.
The laptop has very localized water damage, nothing got dropped over it known but I suspect a few droplets got in with the fan. The corroded parts only affect thunderbolt which should not be needed for a POST. I removed the few corroded caps and resistors from the thunderbolt. Made sure there are no shorts. So its not the issue
CPUIMVP_VR_ON turns HIGH for about 100ms before it pulled low again (Probably because the system resets?)
CPUIMVP_TON stays 8V, but when the system powers on it turns to below 3V (Maybe even 0V, but my multimeter is slow) and then turns back to 8V when the fan starts to stop again. R7402 on pin 2 does not gets pulled down. Its the chip that does it. R7402 is within its 1% allowance
PPVCORE_S0_CPU and PPVCORE_S0_AXG_R stays 0V on the multimeter. But maybe its just too fast for the multimeter to notice. There is no short to ground on these lines, although there is low resistance but thats normal
PPDDR_S3_REG_R quickly turns to about 1.45V before it moves down to less then 0.1V, this keeps going up and down every time the CPU tries to boot. Indicating it goes back down to S4 or less
Any idea's where to look? Thinking about replacing U7400 but I'm always told this chip never dies. Which makes me assume its somewhere else
I don't remember having in any boards with this issue before haha
Thanks again! Let me know if you want me to measure anything
Hey everyone
Going on a nice vacation in a few days, just want to finish this last laptop before I close off and enjoy a break
Laptop has been touched by idiots before, but no signs of soldering or ultrasonic. But they managed to pull off the screw holder for the SSD (How even? You'd have to pull really hard). No short on the surrounding pads and the damage is right now mostly cosmetical.
The laptop has very localized water damage, nothing got dropped over it known but I suspect a few droplets got in with the fan. The corroded parts only affect thunderbolt which should not be needed for a POST. I removed the few corroded caps and resistors from the thunderbolt. Made sure there are no shorts. So its not the issue
CPUIMVP_VR_ON turns HIGH for about 100ms before it pulled low again (Probably because the system resets?)
CPUIMVP_TON stays 8V, but when the system powers on it turns to below 3V (Maybe even 0V, but my multimeter is slow) and then turns back to 8V when the fan starts to stop again. R7402 on pin 2 does not gets pulled down. Its the chip that does it. R7402 is within its 1% allowance
PPVCORE_S0_CPU and PPVCORE_S0_AXG_R stays 0V on the multimeter. But maybe its just too fast for the multimeter to notice. There is no short to ground on these lines, although there is low resistance but thats normal
PPDDR_S3_REG_R quickly turns to about 1.45V before it moves down to less then 0.1V, this keeps going up and down every time the CPU tries to boot. Indicating it goes back down to S4 or less
Any idea's where to look? Thinking about replacing U7400 but I'm always told this chip never dies. Which makes me assume its somewhere else
I don't remember having in any boards with this issue before haha
Thanks again! Let me know if you want me to measure anything
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