HP Envy 360x 15-fh0003na MB: PB51 LA-M798P

[Fryderyk Nietzshe]

Hi All.
I am looking for schematics and/or boardview for aforementioned Laptop.
Make: HP
Model: Envy 360x 15-fh0003na
Motherboard: PB51 LA-M798P REV: 1.0
SN: CDN34213TN

I am looking for this due to suspicious component around EC chip. I did pointed it in the attached photo. First impression was that it is a discolored and shorted Cap, but after closer look it is probably a resistor. Either way the part is a total short and the readings of the line are as noted. Does anyone know parameters of this component? Or have a schematics for this laptop??

From probing around the board both cold and with power this looks like only one suspicions place. And the laptop does goes with diagnostic blinks - 5 long, 3 short.
To be ahead of suggestions about bios being at fault i already tested the behavior with some virgin bios but no change, so for the time being i did crossed out bios corruption

Thanks in advance

[Marcin_eS]

Cześć.
Mam podobny laptop i podobny problem.
I have a similar laptop and a similar problem. Mine is an HP Envy 15-fh0023dx, but the same LA-M798P Rev. 1.0 motherboard. After turning it on, the capslock blinks twice, the power LED goes out, then it lights up, and the capslock starts blinking sequentially with a code of 5 long, 3 short. Of course, there's no display. I have all the voltages, the APU gets warm. The BIOS has also been replaced several times. The EC chip has also been reflashed. There's no schematic available, nor is there a boardview online, and the situation looks hopeless, as anything could be faulty: the APU is unsoldered, the RAM solder joints are cold, or a single PCB component has broken off—a real rabbit hole.

What you posted in the photo is probably some kind of 0 Ohm resistor, choke, ferrite bead. This is sometimes done by connecting digital GND to general GND. Mine also has a low resistance to ground, around 0.1 ohm.
You could try desoldering it and see if any voltage appears on the pins or if it changes anything. It probably won't damage anything else. I'm afraid I won't be able to resolder such a small component.
Regards, Marcin

[Fryderyk Nietzshe]

Cześć.
Mam podobny laptop i podobny problem.
I have a similar laptop and a similar problem. Mine is an HP Envy 15-fh0023dx, but the same LA-M798P Rev. 1.0 motherboard. After turning it on, the capslock blinks twice, the power LED goes out, then it lights up, and the capslock starts blinking sequentially with a code of 5 long, 3 short. Of course, there's no display. I have all the voltages, the APU gets warm. The BIOS has also been replaced several times. The EC chip has also been reflashed. There's no schematic available, nor is there a boardview online, and the situation looks hopeless, as anything could be faulty: the APU is unsoldered, the RAM solder joints are cold, or a single PCB component has broken off—a real rabbit hole.

What you posted in the photo is probably some kind of 0 Ohm resistor, choke, ferrite bead. This is sometimes done by connecting digital GND to general GND. Mine also has a low resistance to ground, around 0.1 ohm.
You could try desoldering it and see if any voltage appears on the pins or if it changes anything. It probably won't damage anything else. I'm afraid I won't be able to resolder such a small component.
Regards, Marcin

Thanks for shedding some light on this particular component. Your explanations seems quite possible. I will check the voltage with component removed. My current best thinking with the reports connected to other HP devices is cold solder under RAM. If I will be unable to find any other suspicious area i will try to reflow RAM - this will be a bit tricky as there is some glue for flex protection. From my experience this is overall common issue in modern laptops.

PS. Dzięki

[Marcin_eS]

Cześć.
I've already tried reflowing the RAM, but it didn't help at all. I thought the RTC and 48MHz clocks weren't working, so I measured them, and they're fine. It's a hopeless case, and the board looks like it came straight from the factory.

Does your board behave like mine? I mean, when you turn it on, the power LED lights up, the fans start running, after a moment, the caps lock blinks twice, the power LED immediately goes out, after a second it lights up again, and now the sequence of 5 long, 3 short appears? No backlight, no USB communication, and no keyboard activity at all.

Pozdro,
Marcin

[Fryderyk Nietzshe]

Cześć.
I've already tried reflowing the RAM, but it didn't help at all. I thought the RTC and 48MHz clocks weren't working, so I measured them, and they're fine. It's a hopeless case, and the board looks like it came straight from the factory.

Does your board behave like mine? I mean, when you turn it on, the power LED lights up, the fans start running, after a moment, the caps lock blinks twice, the power LED immediately goes out, after a second it lights up again, and now the sequence of 5 long, 3 short appears? No backlight, no USB communication, and no keyboard activity at all.

Pozdro,
Marcin

Yes. The symptoms are the same. Quite an interesting one, especially, since the codes are quite obvious and simply denotes that there is no communication between bios end EC or RAM. I wonder if you tried to flash new EC or just reflash the original one? I unfortunately does not have programmer that allows me to dump EC so i cannot check this part. And one more thing. Did you reflow EC? (I assume yes since you already went for RAM)

[Marcin_eS]

Cześć.
My laptop was in for service, and the initial diagnosis was that the EC chip software was corrupted, and they had no way to get the correct software. So I provided them with the software extracted from the official BIOS package from HP's website. After that, they informed me that they had replaced the software (SVOD4 + software), which, according to them, turned out to be identical to what I had provided. This didn't yield any results.

There's no communication on the BIOS chip pins, and communication from the SPI bus goes directly to the APU. The next diagnosis was a faulty APU, but they didn't have a new one to replace it with.

I didn't do a full reball of the RAM, just a reflow, to make it float. Maybe one of the chips is damaged, but I don't have any spares, and I don't have stencils either. And yes , EC chip has been refowed too.
I don't want to tear this apart thoughtlessly. The correct thing to do would be to track the boot sequence and determine the culprit based on that. But without a schematic and boardview, that's a detective's job, not a service technician's.
Pozdro, Marcin.