HP Spectre X360 (Quanta Y0D) Not Charging, No Power

[Dannyx]

Good day folks. It's been a while since I've worked on a laptop, but this one belongs to a very important person - my boss ! - so I'd be great if I could get this one going, but the signs are not good so far. I found the schematic AND boardview right here on our forum - big shout-out to SMDFlea for providing them !

The laptop doesn't do anything: totally dead. No lights, no power, no fan-spin. I took the cover off and noticed someone had been inside before, as two caps are missing (PC20 and PC29) which are just power-input filter caps, so it SHOULD work without those too.

I took some measurements and I do get 19v from the adapter coming into the board, so our main power rail +VIN is present. Other than that though, no other voltage comes on.

Long story short, I think the problem is PU4, which is a BD99990Gu - an IC I couldn't find any info on. It's responsible for ALL power rails in the system and since none are coming on and I couldn't find any shorts, I'd blame it.

Interesting to note: the battery was completely flat. I unplugged the connector and tried charging it on my bench supply but couldn't: it was taking no power through the connector. I took it one step further and peeled away the plastic film on the battery to expose the cells directly and NOW I was able to feed power into it directly, being careful not to pump too much current into it. Still, it wouldn't go through the connector, so the management chip in the pack is probably keeping it off. This should be of no importance at this stage, since it should run without the battery, HOWEVER:

Ironically, SOMETIMES, God knows when and how, when I reconnect the battery, the orange light comes on ! Even more annoying, now all of a sudden I (obviously) DO get 3.3v (+3VPCU) on its coil (PL10), since I have a light ! It doesn't stay on forever though and it makes no difference if I plug in the charger NOW. The same happens with my bench power supply (ignoring the "sense" pin): it doesn't draw any power at all on the DC jack. One time however, I noticed the light was staying on more than usual - the laptop was on and was displaying a picture ! It stood there for a good 30 seconds before shutting off on its own as if it was running on whatever charge it had left in the battery ! What's going on ??? So, PU4 DOES work......but only when it feels like it and I have no idea what could be causing it. Is it the chip itself, or something else ?

It could be because of the sense pin and the laptop is working fine, but simply refuses to charge, so it ran on whatever trickle of a charge it had left in it from when I powered its cells up. I tried it with the bench supply most of the time, but also found an adapter from another HP laptop which fits the connector, however it could be there's some form of communication going on between the adapter and the board via that pin, so despite the adapter being and HP and matching the connector, it's STILL not enough ! What do you guys think ? Thank you.

[reformatt]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

Some battery controllers will disable the output pins until a logic line is grounded or has volts applied to it. Looking at this one, you have 3V_RTC on pin 7 which should enable it. Presumably, this is from the coin cell battery so check if it's present. If the cells in the battery are completely discharged though, the controllers will refuse to charge them at all. Safety measure as the cells are deemed faulty at that point.

I'd initially be concentrating PU1, PQ8 and PQ1. Also check DC Jack for damage, as there is a AD_ID sense pin going to the EC. Sometimes the jacks collapse and you end up getting 19V straight up the AD_ID pin into the EC. Although this one looks like it has 2K and a zener to at least protect the EC in this instance.

[Dannyx]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

Some battery controllers will disable the output pins until a logic line is grounded or has volts applied to it. Looking at this one, you have 3V_RTC on pin 7 which should enable it. Presumably, this is from the coin cell battery so check if it's present

There's no coin cell on this board, which is typical of laptops with non-user-removable batteries. Looking on page 7 of the schematic, in the right pane, if I understand correctly, +3V_RTC is basically +3VPCU through D9, however +3VPCU comes from PU4 (page 29), but this is not happening. The chip itself is probably not faulty, but simply refusing to turn on because of the ID pin in the charger. I'm not sure what gets the battery to "output" again, because even after charging the cells themselves to around 11.3v, I get nothing on the red/black wires and as previously established, if I simply apply 12v to the battery terminal, nothing happens, probably because of lack of communication between the battery and the board.If the cells in the battery are completely discharged though, the controllers will refuse to charge them at all. Safety measure as the cells are deemed faulty at that point.

I'd initially be concentrating PU1, PQ8 and PQ1.

I think those are alright, because I DO get +VIN with the charger connected, just none of the sub-rails.

Also check DC Jack for damage, as there is a AD_ID sense pin going to the EC. Sometimes the jacks collapse and you end up getting 19V straight up the AD_ID pin into the EC. Although this one looks like it has 2K and a zener to at least protect the EC in this instance.

I checked the jack and it appears to be fine: it looks fine visually and doesn't read a short between the power pins and the sense pin.

At this stage, I asked the guy to try and source the original adapter, since I'm pretty sure he has a busted cable which no longer provides the sense pin, so the laptop just ran on battery until it completely died and then refused to charge. I'm also planning on getting a cable with the small blue jack that fits the connector (the kind you use to fix adapters with broken cables) and try experimenting with different voltages on that center pin (within reason, of course). Not that long ago, I managed to trick an older HP laptop into running on a random adapter by building a voltage divider which sends around 6v on that center pin, according to some sources I found online. I tried connecting JUST the 19v output and the charge light just blinked 3 times and the laptop wouldn't run on the charger. That one has the big round plug, as opposed to this small "blue-tip" one and I even have an adapter "pigtail" which converts that big one into this small one, since it's essentially pin-for-pin compatible - just passes the AD_ID pin through untouched. What I DON'T have is an original HP adapter of high enough wattage to try, so what I did was plug the pigtail adapter into the laptop and then used another adapter to go from 3-pin large plug to a regular DC jack, which of course does away with that center pin, so no power for you.....

Seems to me the best bet is to have a "big" HP adapter AND a pigtail adapter on hand, so you're set for both situations.

[Dannyx]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

Ok, UPDATE: I tried some more stuff today: I got my hands on a known good HP charger which has the large barrel jack and center pin and tried using it through the pigtail adapter to convert it to the small jack. The voltage on the center pin is indeed 18v when unplugged and drops to 0.5 when plugged into the laptop. It's not because of the DC jack - I also get 18v there if the DC jack is disconnected from the board end.

I then went ahead and checked the components around the AD_ID pin (page 27 of schematic) and they all read fine. No direct shorts to ground or values out of spec. I had my money on PD6, but it also checks fine.

I also tried powering the center pin (pin 6 of the connector) with 5v from my bench supply, WHILE still having the DC jack connected and supplying 19v to the board, but nothing happened: I didn't see a surge in current on my power supply to indicate a direct short across U8, but I got no light or power either. I'm not sure why the adapter drops all the way down to 0.5 when plugged in, but the power supply doesn't show any current draw at all...it could be because the diode is bad despite reading fine on my meter ? Like if it breaks down under a high enough load ? This would also mean U8 is pretty much f*cked at this point too, as the AD_ID pin goes straight to it and it just ate 18v....

I also noticed I'm not actually getting +VIN now either, so PU1 is not working (I think this is the equivalent of PPBUS_G3H on Macs)....whereas with the floating center pin and the aftermarket adapter I DID get it, but no sub-rails....this is getting weird

[piernov]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

45W HP AC adapter → ~500kΩ upper resistor
AD_ID = 19 V x 12.1 kΩ / (500 kΩ + 12.1 kΩ + 100 Ω) = 0.45V

I also tried powering the center pin (pin 6 of the connector) with 5v from my bench supply,

High chances of damaging EC.

[Dannyx]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

45W HP AC adapter → ~500kΩ upper resistor
AD_ID = 19 V x 12.1 kΩ / (500 kΩ + 12.1 kΩ + 100 Ω) = 0.45V


High chances of damaging EC.

Thanks. So the 500K resistor is inside the adapter ?

I'm using a 90w adapter with the pigtail in this case, so I'm getting 0.55v there.

ACOK pin of PU1 reads 3.3v
REGN pin (pin 16) reads 6v
VCC pin (pin 20) reads 19v
ACDET pin (pin 6) reads 2.8v

I assume PD6 would've clamped whatever I applied to it, since I didn't come with 5v after the resistor PR105 and PR103 - I tried it straight at the DC jack input and didn't go over 5v, so I hope that didn't damage anything.

I'm also pretty sure PQ8 is shorted D-S (but not G. PR88 also reads fine - 4K). Pin 4 ACDRV reads 20v and 19v after PR88. I'm not sure how/IF this is somehow detected by PU1 and it refuses to run....

[Dannyx]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

I also noticed something about PU1 which I don't understand: when just the battery is connected, how does PU1 operate ? There doesn't seem to by any power getting to the chip itself, as the VIN pin comes from the adapter, not the battery.....does the IC even operate at that point ??? The datasheet says it can cut off the battery if the voltage gets too low, so how can it "act" on PQ28 if the chip is not powered ???

[Dannyx]

Re: HP Spectre X360 (Quanta Y0D) Not Charging, No Power

Ok, laptop's working now: I first replaced PQ8 with something similar I pulled off a donor board. It still wasn't working: now I was getting something on the VIN pin, but it was not enough: only around 5v and it seemed to be jumping up and down. The other rails were obviously still dead. Upon closer inspection, I also noticed PR89 had a crack in diagonally, which I'm positive wasn't there the first time I checked the board. It was also open, as opposed to the 10 ohms it was supposed to read ! No idea how and when this happened, but I scrounged up another one and replaced it. I was afraid PU1 itself was shorted internally and killed the resistor, but thankfully it wasn't: laptop is now working