ASUS G14 GA401QM Charge Light w/ No Power On

[ResoluteHawk]

So I have yet ANOTHER Asus Zephyrus GA401QM. The problem with this one is that the charge light will turn on when plugged in but it will not turn on when the power button is pressed. Immediately I would think that the PCH is dead/shorted to ground.

Measurements on the BIOS chip and 3.3V coil say differently however. The 3.3v coil on the board measures 3.4k ohms and the BIOS chip measures 607 Ohms. When compared to a working board the values are roughly the same so the PCH is likely healthy.

CPU VCORE coils measure 4.8 Ohms and the one on the right side (SysAgent?) measures 9.0 Ohms.
GPU VRAM measures ~30 Ohms and this is Samsung memory.

When power is plugged in, the board "starts" but doesn't actually turn on (keyboard lights don't turn on, fans don't spin, CPU and GPU don't get hot, etc). No heat spots under a thermal camera even with the heatsink off.

I can measure 5v and 3.3v on their respective coils.

The CPU and GPU Power IC chips (PU8001 and PU9101) are not receiving power. PU8001 is a UP9505PQGW.

On PU8001, 5v is not present on Pin #14 when power is plugged in. Pin #15 is not measuring 3.3v either so this chip isn't even turning on.

I don't know where to go from here. No shorts around the Super IO.

Schematic and Boardview ---> https://www.badcaps.net/forum/showth...96#post1246796

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Just to update this post; 1.2v is not present on PL8601.

Further, the 3.3v Power Good signal is not present on Pin #10 of PU8601, and the 0.6V VTT is completely missing from Pin #2 and Pin #20, however it does receive 5V on Pin #12 so the chip is turning on.

Given that both VTT and the 3.3v PGood signal are both missing, is it safe to say that this IC needs to be replaced?

Very confusing because it doesn't seem to be generating VTT or the necessary 1.2V_PWGD signal, but resistances around the chip are consistent with a working chip.

[mcplslg123]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

pu8601 pin7/8 are enable for this IC. What is the voltage on pin7/8 as well as pin9?

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

The schematics clearly describes that the SPI flash isn't powered by +3VS but from +1.8VSUS. Also it is a AMD platform, so no PCH present. A partial shorted +1.8VSUS points into the direction of a bad FCH anyway.

The schematics is pretty detailed, with a power sequence included. Follow it.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

pu8601 pin7/8 are enable for this IC. What is the voltage on pin7/8 as well as pin9?

Voltage on Pin #7/8 is 0v, and Pin #9 measures 19.17V (seems high).

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

The schematics clearly describes that the SPI flash isn't powered by +3VS but from +1.8VSUS. Also it is a AMD platform, so no PCH present. A partial shorted +1.8VSUS points into the direction of a bad FCH anyway.

The schematics is pretty detailed, with a power sequence included. Follow it.

I tried following the power rails as closely as possible and yes it is very detailed. I think I learned how to read board schematics in finer detail with this board alone, even with the mistake I made above with the enable signals.

To my understanding the PU8601 IC is the only chip that supplies/generates 1.2V and it's from Pin #16 (we can see that there is a "VO=1.215V", indicating Pin #16 is an output). Everything else in the schematic seems to be an input signal for 1.2V, and if Pin #16 doesn't have 1.2V, PL8601 isn't going to have it. The chip, however, is not receiving an enable voltage on Pins #7 and #8, and that looks like it comes from the Super IO chip. If the Super IO is not generating those enable signals, it's safe to say that the Super IO needs to be replaced right?

I feel like I'm missing something, but if not, would the above observation be correct?

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Actually it seems we have something like a "communication issue".

No, it is not safe to assume a bad EC since you jumped over the half of the sequence without checking anything. There are tons of power signals and logic signals between +3VSUS and 1.2V_ON and you can't simply ignore them.

P_3VSUS_PWRGD to start with.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Ok so I've followed the schematic even further and actually had to start at the end, which was Pin #3 on PU8805.

This pin needs an enable signal (SUSB_EC#), which looks to be generated from the PCH from SLP_S3_L. The PCH outputs the data signal from AT11 and it then feeds into R0740 and goes to the Super IO chip at GPC4 as PM_SUSB#, then out of the SIO on N2 and into PU8805, which will then generate the +5VS rail.

I am not getting the 3.3v signal on R0740, which is the first place that this enable signal would normally be found when the board is plugged in and turned on. If I press the power button while the board is plugged in, I get a slight jump in voltage on R0740, but it's only 19mV and it turns off after ~2 seconds, so not nearly enough to send a power on signal to the EC, even for a moment.

Looks like it's a problematic PCH after all. Again, maybe I'm missing something but I traced that signal back to it's source and it goes through a via in the board; probe point looks to go through to the data line via the middle layers through to the pin where it is generated (AT11). What's interesting is that PM_SUSB# is 98K ohms to ground so it looks like the PCH just doesn't want to generate the signal anymore.

As for CPU_VRON, it looks like that signal comes out of the Super IO on GPC7, but the SUSB_EC# must be a prerequisite signal. Since the EC isn't getting that SUSB data signal, the CPU_VRON signal won't get sent from GPC7 on the SIO to Pin #15 on the PU8001 chip, hence the missing 3.3v on this pin as discussed in my first post. Also, since Pin #14 on PU8001 operates on the 5VS rail, the chip won't power on because PU8005 isn't receiving power and thus can't talk to PU8001.

Also, the memory IC. This one I'm a little less clear on but my best guess is that since the PCH isn't generating PM_SUSB#, we're not going to get PM_SUSC# either since the PCH likely generates these at the same time or maybe it needs to generate the B one before it can do C?

Anyways, the PM_SUSC# is the enable signal needed for Pin #8 on the memory IC (PU8601).

Sucks lol but this was actually a really fun learning experience (and I got to do some detective work!).

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Correction for the memory IC statement; 1.2V_ON is the enable signal, not PM_SUSC.

Woopsie.

I'm still not 100% on how this gets generated, although it does say that it uses the 5VSUS_ON_EC. So my guess is that the 5V in the SIO gets internally stripped down/converted to the 1.2V on GPE2 then sent out?

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Good for you that you learned a lot from that. Unfortunately it still applies that there is no point to look at these buck converters as long as the enables are not present. Also you seem to have realized, SUSC# is a requirement for SUSB# but that's still to far from where it seems to be stuck, since the last voltage you can measure is 3.3V. I have already asked for measurements, you device whether you want to follow or to proceed like before.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

you device whether you want to follow or to proceed like before.

Wait a second....what did I miss? Seriously I actually want to know. I'd definitely like to go to the end of the road with this one.

SUSC# is a requirement for SUSB# but that's still to far from where it seems to be stuck, since the last voltage you can measure is 3.3V.

I'm confused here. I found that the PM_SUSB# 3.3v signal isn't even being sent from the AT11 pin so isn't the fault here directly related with that specific part of the chipset/PCH/processor?

We wouldn't be measuring a buck converter there but instead it's just a direct data line. The AT11 pin sending out PM_SUSB# seems pretty critical for the system to function.

It's entirely possible that I'm wrong and there is something else going on that I missed. I'd seriously love to know if I'm missing something.

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

The thing with the spoken language is, someone need to understand what was told to act accordingly. So i have to assume we have some kind of a language barrier here, although i repeated where the issue with your troubleshooting is two times already. Maybe this picture is the clue for you that there is no point to troubleshoot late in the sequence while it is not clarified whether it isn's stuck way earlier in. This diagram does not apply exactly to your board but is still good enough to point out the actual issue.

With the measurements you have shared we're in the green box. But instead of troubleshooting further (Blue Box), you're randomly looking at the RAM and VRM Controller. (Red Box). And this is even a partial diagram. there is even more inbetween, which we have to find out by ourselves.

This is not how proper troubleshooting works.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Ah. You're saying that something between the 3VALW and PM_SUSC# triggers AT11 and AV11 to release SLP_S5_L, then SLP_S3_L comes on after SLP_S5_L (they're power states)?

I missed this somehow (I am still what I consider to be a beginner with this).

Completely understand you. No language barrier; sometimes I overlook things and I just happened to overlook about ~50% of the equation here.

I will revisit the schematic and have another look.

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

No, I'm simply saying there are requirements to be met, one after another, before SUSC# even can be deasserted.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

(+RTCBAT)+3VA_RTC => 3.01V
(AC_BAT_SYS)+3VA/+5VA => 3.3V and 5V are present (PU8701 Pin #3 and Pin #13 respectively)
(+3VA_RTC)RTCRST#(PCH) => 2.7V (R0901, SL0906)
(Power)AC_IN_OC#(EC) => 3.3V (SL3021)
(EC)PS_ON(+3VA_EC) => 3.3V (PSL8801)
(PS_ON)+3VA_EC(EC) => 3.289V (PR8820)
(3VADSW_ON)+3VA_DSW(3VA_DSW_PWRGD) => Don't know where to measure this or what DSW is.

(EC)DPWROK_EC(PCH) => Don't know where to measure this or what DPW is.
(+3VA_DSW)PM_BATLOW#(PCH) => Don't know where to measure this or where it is located.
(PCH)PM_SLP_SUS#(EC) => Don't know where to measure this or where it is located.
(VSUS_ON)+1.0VSUS_VCCPRIM(1.0VSUS_PWRGD) => Can't find where to measure this.
(EC)PM_RSMRST#_PCH(PCH) => 1.8V (R0703)
(PCH)SUSWARN#(EC) => Can't find where to measure this.
(EC)ME_AC_PRESENT_PCH(PCH) => Can't find where to measure this.
(EC)PCH_SUSACK#(PCH) => Can't find where to measure this.
(PWR Switch)PWR_SW#(EC) => 3.27V (C5604)
(EC)PM_PWRBTN#(PCH) => 3.362V (R3069)
(EC)SUSC_EC#(Power) => 0V and 31 Ohms to ground (SL3024)
(SUSC_EC#)+12V/+5V/+3V => Don't know where to find this but since the above isn't present these won't be present either right?
(EC)SUSB_EC#(Power) => 0V and 13-15 Ohms to ground (SL3023)
(SUSB_EC#)+12VS/+5VS/+3VS => Don't know where to find this but since the above isn't present these won't be present either right?

The power and data signals seem to stop at the EC if I did this correctly, but I'm not 100% sure since there are signals that I couldn't find. I stopped measuring here because I don't think it would be of much value to measure past this point.

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Well, I told you already, that the sequence I shared here does not DOES NOT APPLY EXACTLY to your board. You need to find equivalent signals then of course.

For 3VA_DSW_PWRGD --->> the PGood from the 3V/5V Controller for example.

We can't do every brainstorming job for you. For being good at chip-level and especially the logic behind you need to be very smart. So try please.

Except you're trolling me here for some reason.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

No I'm not trolling. I'm trying to get help because I don't know what to do or how to do it. I mentioned that I was a beginner at this.

I literally pulled that power sequence from Page 67 of the schematic that I linked in my first post. It just so happens to be roughly the same order.

Seriously...I'd like to learn but I don't know 100% how to trace this stuff. That's why I'm here posting...because I need help.

I never joke around when I'm trying to learn because I aggressively make sure that I understand something. If it seems like I'm not noticing something or don't understand it...it's because I don't. I'll openly admit it. That's why I ask.

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Good, we have clarified that.

Now start with the power button. We want to know whether it does respond as expected to exclude a issue here. I see no other way than to proceed one step after another.

RTCRST# sounds a bit low. Maybe you can share a resistance to GND measurement from there.

[ResoluteHawk]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Resistance on SL0906 to ground is 64K Ohms.

I missed this detail, so to clarify, voltage on both SL0906 and R0901 is:
2.98V when plugged in without the RTC battery
2.72V with just the RTC battery no AC adapter.

C5604 measures 3.3V as soon as I plug in power. Pressing the power button also yields 3.3V on C5604.

[Sephir0th]

Re: ASUS G14 GA401QM Charge Light w/ No Power On

Good, now look whether PM_PWRBTN# reacts accordingly to the power button press. Maybe it does not in case the board is already auto-on till some extent. But it would be nice to have this info to decide where to look next.