P51 Powers but won't Boot to BIOS

[Four]

"I saw a P51 at a fraction of its normal price and thought I should buy it and try to fix it, but I don't know much about this laptop or how to fix it."

Sequence of Fault Events
Plug the laptop into the power jack
the power button blinks thrice
Press the Power Button
the fans spin for a second or two and the keyboard lights up briefly

The laptop powers off

Factors which I Consider Possibly Relevant
-The GPU fan, while it spins briefly, originally made a laboured kind of sound until I removed it from its housing during the diagnostic process
-There is RAM in the laptop (I have tried using different pieces in separate ports)
-fitted a new BIOS battery (I don't know if that would help or even make any difference to a laptop powering on while plugged into the mains)
-There is no Hard Drive fitted
-I don't know the history of this laptop

There is no Beep Code though strangely on my initial start attempt, there was

Any help is appreciated, I want to know if this laptop is fixable, how do I know if it's bricked

[axur-delmeria]

Does it sound an error beep code if you power it on without any RAM installed?

[Four]

with the RAM plugged or unplugged,
press power button
the fans spin for a moment
and there is no beep code.

the fans also spin for a moment when the ac gets plugged in


they seemed to be spin for a longer few moments before but now very briefly

[axur-delmeria]

IMO there's nothing you can do at this point.
It seems to be a board-level fault-- most likely, the repairs would require specialized equipment like a hot-air soldering station at the very least, a BGA rework station at worst.

[Four]

thanks, i figured as much

however, how can i get started fixing it?

does the bios perhaps need flashed?

[Four]

how easy is it to [censored] up a mobo by taking apart the laptop and testing it like this?

[axur-delmeria]

Well, the laptop is already in bad shape, the only worse shape it can be is completely dead.

What you can try is disconnect everything on the system board except the absolute minimum required to power it up. That means:

* Power button
* charging port
* heatsink and fan

Disconnect the LCD cable on the system board side, some system boards blow a fuse if the LCD cable is plugged in but no LCD panel is connected.

If it still shuts down immediately, then it's in a really bad state. You can try flashing the BIOS externally, though TBH I've never done that myself.

[Four]

Having done that, the fan just spins up for a second and then, what is left of P51, turns off.

I have stripped it down to the mobo, the components look okay and it certainly has never been disassembled this far prior, I have sppotted the BIOS chip, i have it in my sights

[Four]

Which of these two is the BIOS chip, please?

[RealBlackStuff]

It is a bad idea to try and flash the BIOS, if you don't even know WHAT the problem is.
You can only make it worse that way!

Apart from that, the chip should have U5 marked nearby and is one of these:
WINBOND W25Q128FVSIQ
MACRONIX MX25L12873FM2I-10G
MICRON N25Q128A13ESEDFF

[H-Atkinson]

Sounds like it may be trying to "learn" the memory config/timings? Let it sit "powered on" for a little while and see what happens. My P53 and P1 Gen 5 both went through this process, and if you've recently unplugged the CMOS battery, that could have something to do with it. Definitely do not try to flash the BIOS... this does not seem like a corrupt BIOS sort of issue at all.

[TPFanatic]

My p71 does the learning process just from installing a usb device in the wwan slot.