DELL XPS 15 9560 - No VCore, Power Off after few seconds

[Sephir0th]

Hello Community,

i'm troubleshooting this one since days and actually i'm really lost because i believe i'm Missing the required experience for an issue Like this...

It is a Dell XPS 15 9560, i7-7700HQ, GTX1050 Board Number LA-E331P Rev 1.0, Most similar to LA-C361P so i use this Schematics.

Issue: Starts and shuts Off after a few Seconds. Basic Troubleshooting (Adapter,RAM,BIOS/EC Flash from alisaler) of course already done, which didn't Changed anything.

I have another working Board with i5-7300HQ and GTX1050, with It's Help i can compare some Things (measurements below). I have Schematics too, but unfortunately It's Very hard to use it because of Missing Board markings. For this reason i wasn't able to measure some Logic Signals so far. Actually i have this Overview:

Coil (Rail-Name) Voltage non-working Board / Résistance to GND non-working / working board

PR300 (+PWR_SRC_AC) 19.9V / O.L. / O.L.
PL302 (B+) 13.6V / O.L. / O.L.
PL400 (+3VALWP) 3.389V / O.L. / O.L.
PL401 (+5VALWP) 5.179V / O.L. / O.L.
PL501 (+1VALWP) 1.014V / 9.3 Ohms / 82.9 Ohms (!)
PL600 (+1.2V_DDR) 1.191V / 140 Ohms / 144 Ohms
PL701 (+1.35VSDGPU) 1.381V / 80 Ohms / 280Ohms (!)
PL801 (+VCCIO) 0.972V / 56 Ohms / 24 Ohms
PL901 (+1.05VSDGPU) 0V / 360 Ohms / 217 Ohms
PL1002 (+GPU_CORE) 0V / 1.7 Ohms / 2.0 Ohms
PL1200 (+VCC_CORE) 0V 4.5 Ohms / 1.9 Ohms
PL1300 (+VCC_GT) 0V 7.6 Ohms / 4.0 Ohms
PL1306 (+VCC_SA) 1.068V 26 Ohms / 10 Ohms
PL1500 ( unknown ) 0V 79 Ohms / 55 Ohms (0.8V at working Board)

My observations so far:

After Plugging the charger it Starts itself and i have only +5VALWP, +3VALWP, +1VALWP, +1.2V_DDR, +1.35VSDGPU, +VCCIO and +VCC_SA present. Everything Else isn't Coming Up at all. After a few Seconds i lost everything except the ALWP Voltages. If i repeat Pressing the Power Button, i get the lost voltages Back, but again Just for a few Seconds. The Enables e.g. RUN_ON_EC, VR_ENABLE going Low causing losing +VS Voltages.

I can't find the reason for the Low Résistance of +1VALWP. I've already Opened some Jumper and removed some ICs from this Rail but it Changed nothing so i decided to Put everything back. The Rail draws 0.12 Amps when injecting, nothing getting hot or even warm.

Also i Wonder whether the Low Résistance at +1.35VSDGPU could be fine compared to the working Board. When i inject Here, 1.37 Amps are drawn and the GPU is getting warm after a while.

When injecting on 3.3VALW-Rail, there are 0.06 Amps drawn for about 10 Seconds, then Only 0.02 Amps drawn. Nothing getting hot or even warm.

I was able to check some signals (while the 7 Seconds, the Board is on): RSMRST# high, RTCRST# high, PLTRST# low, but resistance is in KiloOhms of every Rail.

PGOOD signals:

3.3V/5V-Controller OK
1V-Controller MISSING, but also missing at working board
RAM-Controller MISSING, but also missing at working board
1.35VSDGPU OK
VCCIO MISSING, but also missing at working board
CPU-Controller OK, but ---> ALERT# low(!), so i have problem with "SVID". Actually i think about dead CPU, bevause SVID Clock and Data comes more or less directly from CPU...

I compared the whole VRM-Controller and the Power stages with the working Board and didn't find anything suspicious. Only some little differences in Resistances, but they could easily explained because of the different CPU (i5 instead of i7) soldered there. However, i already ordered the parts for the VRM-Circuit and also the MEC5085-LZY.

Actually i'm Not Sure where to proceed or whether it makes any Sense to proceed in General because of the low resistances i found. Hopefully Someone Here has experience with an issue Like this and can move me in the right direction. Otherwise i would Start replacing the components at VRM Circuit with "Fingers crossed".

Note: there are some small differences, but the Schematics fits to.. let's say 95% regarding what i have checked so far...

[piernov]

Re: DELL XPS 15 9560 - No VCore, Power Off after few seconds

+VCCST and +VCCSTG?

[Sephir0th]

Re: DELL XPS 15 9560 - No VCore, Power Off after few seconds

+VCCSTG comes Up with 1.008V and measures 282 Ohms to ground.
+VCCST comes Up with 1.019V and measures around 400 Ohms to ground.
The behaviour is like the other VS-rails. Came up for Just a few Seconds.

Bad News, right?

[Sephir0th]

Re: DELL XPS 15 9560 - No VCore, Power Off after few seconds

I have to correct my +VCCST measurement:

1.006V for a few seconds and exactly 365 Ohms to ground

[Sephir0th]

Re: DELL XPS 15 9560 - No VCore, Power Off after few seconds

Hello again!

with the Boardview from >> HERE << and the Schematics of LA-G341P i was (hopefully) able to point out exactly what is missing.

It's just PCH_PLTRST# staying low (0.000V) although PCH_PWROK and IMVP_VR_PG coming out before. Don't sure whether this makes a difference but DDR4_DRAMRST# also staying low (0.060V).

UH7 should be fine. Don't see the point to replace it.

PCH is gone, isn't it?

[laptopuri]

Re: DELL XPS 15 9560 - No VCore, Power Off after few seconds

Hy Iam from Romania and have xps 9550 at wich VSDGPU 1.35V dosn't apear . Did you solve your 9560 ?
https://************/threads/xps-15-...a-c361p.19533/

Here are more docu . thanks