msi gs75 stealth 10se no 5V

[Dcortest]

Hello all,

I'm trying to fix a msi gs75 stealth 10se, at the beginning ic tps51285b get hot connecting the power supply. I desolder the ic and resolder it and for a while I got 3.3 and 5V on Vreg3 and Vreg5 but now I only have 3.3V on Vreg3 but on Vreg5 0V.

VO1, SW1 and SW2 looks like are shorted to groung even desoldering the 1285b, mosfet near to the ic are not shorted.

I would appreciate any help you can provide

[mcplslg123]

Re: msi gs75 stealth 10se no 5V

Exact resistance to GND on VREG3 and VREG5? Dont put power without 1285B being soldered.

[Dcortest]

Re: msi gs75 stealth 10se no 5V

Thanks for your response.
The TPS51285B resistance values to ground (without power supply connected) and voltages connecting the power supply

Pin 1 CS1 6k
Pin 2 VFB1 12k
Pin 3 Vreg3 212ohms -> 3,3V
Pin 4 VFB2 8.5k
Pin 5 CS2 8k
Pin 6 EN2 100k
Pin 7 PGOOD 10k
Pin 8 SW2 0 ohms. (second reading value 1k)
Pin 9 VBST2 ol -> 2,2 v
Pin 10 DRVH2 140k
Pin 11 DRVL2 140k and increase -> 19V
Pin 12 VIN 15k and increase
Pin 13 Vreg5 732 ohms
Pin 14 VO1 0 ohms
Pin 15 DRVL1 140k
Pin 16 DRVH1 145k
Pin 17 VBST1
Pin 18 SW1 0 ohms
Pin 19 VCLK0 ohms
Pin 20 EN1 100k

The voltages are 0V for the rest of the pins

[Dcortest]

Re: msi gs75 stealth 10se no 5V

More tests:
+3,3VALW rail is present (all rail
+3,3VSUS rail is 0.82V when pressing the power button
+5 VALW is not present
+5 VSUS is not present

Maybe TPS51285B is faulty and it's not producing the 5 and 3.3 necessary?

[mcplslg123]

Re: msi gs75 stealth 10se no 5V

Resistance to GND on VREG3 as well as VREG5 is too low. Should be in kilo ohms. No point replacing the IC unless resistance to GND on vreg3/5 is fixed.

[Dcortest]

Re: msi gs75 stealth 10se no 5V

But i jave 3.3 on vreg3...
So where do i have to check to solve the low resistance value?

[Dcortest]

Re: msi gs75 stealth 10se no 5V

Checked vreg5 and it's meassuring 1Mohms

[mon2]

Re: msi gs75 stealth 10se no 5V

Vreg5 resistance is fine. On this ‘B’ regulator version, the ldo rails should be fixed on. See tables #1 and #2 in the data sheet for full details.

The switching output rails should not be a low resistance value. Confirm the measurements again. Share a fresh picture of the reworked regulator area. Perhaps an underside solder short? Flux it well and allow low air pressure to make the part swim into place with a gentle push of the tweezers held by 2 sides of any corner. Watch Louis’ videos on YouTube for guidance. ‘Make the part dance’ will correct hidden solder shorts, if present. Be patient so the pads are not torn off the pcb!!

[Dcortest]

Re: msi gs75 stealth 10se no 5V

thanks mon2 for your response i'll rework the ic to be sure it's well soldered also tomorrow I'll receive a new 1285B IC to double check (also a ene9028b)

[Dcortest]

Re: msi gs75 stealth 10se no 5V

I replaced the TPS51285B and now i'm having both LDO voltages but still missing 5Vsus and 3.3Vsus. ENE IC is sending 3,3V to tps51285 Enable pins, now i'm a bit lost what to check.

[Dcortest]

Re: msi gs75 stealth 10se no 5V

with power supply connected with thermal camera shows tps1285 and ENE chip getting hot. Maybe next step is replace ENE9028 chip

[Dcortest]

Re: msi gs75 stealth 10se no 5V

This is my blog to post my first laptop repair hahahaa.
Now I'm having all rails with the correct voltage, with thermal camera I see tps51285 and ENE9028Q is hot and when I press power button also PCH is warming (not too much) but doesn't power on.

[Dcortest]

Re: msi gs75 stealth 10se no 5V

Right now I have tried to connect my ch341a to ENE9028Q to check if I can connect to it and read/write data
I can read/write data succesful and applied a new EC firmware from MSI website.
Now when I power on the laptop the light start white and change to orange, CPU fan spin and CPU and GPU is getting hot, but I don't have image, no led is powered on keyboard.
So my question now is... is it possible that ENE chip could be faulty? neoprogrammer can detect it and write without issues but is it possible that some parts are wrong and not activating the rest and post bios?
BIOS was updated to latest version (downloaded from MSI website) with the same result

[ethics]

did you ever swap ENE chip? did it boot?

[Dcortest]

did you ever swap ENE chip? did it boot?

Yes, I swapped ENE Chip and reprogrammed it and the laptops boots but also have error 43 on dGPU so no HDMI or displayport video only can use the laptop screen, next step is build a DYI reballing station to reball GPU or replace it.