HP Spectre x360 -DA0X36MBAE0 wont turn on after battery change - Chip identification required

[AJ847.63e]

i all,

Cab anyone identify this chip? Pics attached. It's marked L8=6E 74L.

History: laptop came from a e-cycler. Dropped off a few laptops wanting to get rid of them so he asked if we wanted them, apparently he tried swapping the battery on this one and acidentally broke the tip of the battery connector and plugged the battery in upside down.
All readings on the battery pin seem normal though (comparing to a working same model board).
Connecting the charger you can see the above mentioned chip pulsing so it looks like its going into protection mode, but checking diode mode readings everything matches the readings I get on my known good board.
That said that does not mean the chips not faulty, so I wanted to see if anyone could identify it so I can get a replacement. Would rather not ruin a known working board.

Thanks for your assistance.

[mon2]

Search for ‘L8= Richtek’ on google.

Results in RT6256BGQU.

[AJ847.63e]

Thank you. Dam none of our donor boards have em so I’ll have to order them in.

very strange that the diode mode measurements on the chip itself and the battery connector are the same between this board and the known good.

[AJ847.63e]

Does anyone know if there is any boaedviews / schematics that are similar to this model since the exact ones are not available? I found a tiger lake one which looks similar physically but components wise it’s completely different.

[mon2]

The last pic of the chip appears to show a crack on the top of this component. This part is damaged.

[AJ847.63e]

That was just crap from my cotton swab, took me a good 15 minutes of ipa and different variations of markers and an angled torch to try fill in the writing to make it legible.

[AJ847.63e]

Unfortunately, it wasn't the RT6256BGQU.Caved in and swapped it from the known working board but still same symptoms. 😓.

What else would you expect to get damaged when plugging in the battery upside down? Battery connector diode readings match the known good so I'm puzzled.

Only thing getting slightly warm apart from the 3.3/5V LDO is the TPS on the back of the board but its only getting to 38c and all its pins match the diode measurements on the KG board.

[mcplslg123]

Measure Resistance to GND on all coils/3V LDO/5VLDO

[AJ847.63e]

Looks like the PCH has been hit, popped it under the thermal cam and removed the heatsink and you can see the tip of it pulsing in sync with the LDO chip.

Coil resistances starting from the top left of the CPU 19.5 4.8, 4.8, 7..

[mcplslg123]

Incomplete reply to post#8. So cant confirm anything.

Btw, that's not the way you diagnose whether a pch is faulty or not.

[AJ847.63e]

Sorry didn't do the rest because I thought there's no point if the PCH is cooked.

Starting from the small one on the bottom left of the board (charging port side):
20k, 20k, 20k, OL, 67 (Bottom left cutout of copper RAM shield), 73, 52, 71, 21K.

What do you mean that's not a way to test if the PCH is faulty? I thought it should not be getting extremely hot in just one point where the rest of the die is stone cold. Diffused spread out heat yes that would be fine, as it's generating it's rails. But not just the top tip of it. I'd post a pic, but it blinks so fast I can't get it.

[mcplslg123]

Still resistance to GND measurement on 3V ldo and 5V ldo not shared.

[AJ847.63e]

3v3 LDO = 6.5K

Does this chip have a 5V LDO? According to the datasheet that is only for the C variant (RT6256C)

[mcplslg123]

Pllease specify which TPS ic is getting warm.

[AJ847.63e]

TPS65988

[mcplslg123]

Its PD controller. What's the resistance to GND on LDO_1V8 & LDO_3V3? Check whether SDA/SCL lines are showing low resistance.

[AJ847.63e]

LDO_1V8: 1.8M
LDO_3V3: 53.6
SDA: 21.8K
SCL: 21.8k

[mon2]

LDO_3V3: 53.6

Ohms?

[AJ847.63e]

No, 53.6K. And thats both on this board and on the other board that was working.