Hi,
I've got a Surface Laptop 1 first gen that I've been working on for a few days now. I've been diagnosing it and I've been stumped.
When you turn it on, you get the Microsoft logo for 2 seconds, then it reboots, same thing, a total of four times before it turns off and the LED on the charger blinks, indicating a reset. I got the schematics for it (and initially worked with the SL2 schematics) and checked all the powerrails: everything except VCORE and VCC_GT was working fine, and it was constantly rebooting, therefore pulsing all the powerlines. The CPU also wasn't heating up at all.
At my latest attempt of diagnosing, I didn't wait long enough before plugging it in after using my hot air gun and: suddenly VCore was there and the CPU started heating up!
So the device ONLY stays on without bootlooping 4 times and then turning off if the CPU power management IC (Intersil) is heated up. Not sure if it would turn on past that, as I have yet to try more. I've already tried replacing the crystal oscillator that drives the SAM (KBC), thinking that the SAM is constantly powercycling the device before VCORE can be established.
My current running theory is that the CPU oscillator might be shot, and I do have an identical spare, but I am having issues desoldering the original, it just won't come off the board.
Does anyone have any other ideas?
EDIT:
I did some more testing and it seems like VCORE appears if I heat the CPU up for 3-ish seconds
I've got a Surface Laptop 1 first gen that I've been working on for a few days now. I've been diagnosing it and I've been stumped.
When you turn it on, you get the Microsoft logo for 2 seconds, then it reboots, same thing, a total of four times before it turns off and the LED on the charger blinks, indicating a reset. I got the schematics for it (and initially worked with the SL2 schematics) and checked all the powerrails: everything except VCORE and VCC_GT was working fine, and it was constantly rebooting, therefore pulsing all the powerlines. The CPU also wasn't heating up at all.
At my latest attempt of diagnosing, I didn't wait long enough before plugging it in after using my hot air gun and: suddenly VCore was there and the CPU started heating up!
So the device ONLY stays on without bootlooping 4 times and then turning off if the CPU power management IC (Intersil) is heated up. Not sure if it would turn on past that, as I have yet to try more. I've already tried replacing the crystal oscillator that drives the SAM (KBC), thinking that the SAM is constantly powercycling the device before VCORE can be established.
My current running theory is that the CPU oscillator might be shot, and I do have an identical spare, but I am having issues desoldering the original, it just won't come off the board.
Does anyone have any other ideas?
EDIT:
I did some more testing and it seems like VCORE appears if I heat the CPU up for 3-ish seconds
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