Bypass Sony SVE151E11M thermal protection? (schematics provided)

[Bartoloni]

Hi, lastweek i received a Sony SVE151E11M, that after a liquid damage was not starting, after removing oxide and reworking IC and SMD component thet laptop was able to start and was working for 2 DAYS...
after the 2nd day, the screen become black (no backlight), there is HDD activity (OS is loading) but no screen on internal panel, VGA and HDMI.
After 25/38 seconds the computer shut down by itself. (i know that is probably not the cause of the blackscreen but a thermal protection of some kind.. but i'm interested on how the shutdown is performed)
BTW... 2 ICs related to thermal protection was involved on the liquid damage.

the 2 IC are Q14 and U21 (and related caps and resistors), i checked all traces and joins and it's everything ok ( and the computer was working for 2 days after the repair )

on Schematics i saw that these 2 ICs are related to G717 (that is a thermal protection IC with multiple inputs)

Now i'm asking if anyone has an idea on how to prevent the shutdown of the computer by-passing the G717 IC check... (maybe providing 3.3V on "ok" signals)

i provide schematics, photos, images of the circuits and i can answer to any question about measurement.

Thank you in advance for any help (P.S. i checked with my thermal camera, and there are no components ICs/CPu/GPU that reach >55°C ..)

[mon2]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

What is the voltage of SHDN# when logic board is on?

This line, when logic low, will force a shutdown of the board.

Test it. Apply a ground pin to the same line and board should shut down.

Remove each 0 ohm resistor to allow this signal line to float. Is there a pull up resistor on this line on the board?

It may be required. A value like 10k-47k to +3v3 should keep the board on.

[Bartoloni]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

hi Mon2! 5.05V on SHDN#

PR429 PR440 Pr441 pr430 are fisically just jumpers (no SMD component)

can be the G707 damaged? because the signal is always 5.05V

[mon2]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

The label SHDN# has a the '#' as a suffix which denotes this signal to be active_low. That is, when this line is LOW, the shutdown event will occur.

If you are observing a logic high (5v in your case), then this is not the root cause of your shutdown.

Something else on this logic board is causing this shutdown after xx period of time.

To test, you can desolder this thermal sensor IC if you feel comfortable.

You should see the same shutdown event with the absence of this IC.

If any of these thermal sensors trigger then the output of the comined signals = SHDN# will become a low voltage rather than the 5 volt level.

The outputs are OR'd together so if ANY of the thermal sensors are triggered due to high temps, this output will be come LOW (perhaps ~0 volts) to force a shutdown.

[Bartoloni]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

can you exaplain me how the +3V_WAKE and +5V_WAKE works?
why these are connected to a VCC?
why there is also a second +3V_wake connected to Vtrig?
sorry but i have not experience with similar ICs ...


i have 1.395 V on pin 1 (VTRIG)

[mon2]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

The thermal sensor @ G717 needs to be powered. The power rail pin is Vcc.

This sensor can be powered by either 3v3 OR 5v0 - the decision is made by which 0 ohm resistor is assembled on the PCB. 0 ohms is much like a short / jumper.

If PR503 is stuffed at PCB assembly time (aka PCBA) then the sensor will send out 3v3 signals as outputs.

If PR504 is stuffed at PCBA time, the sensor will send out 5v0 signals.

BOTH resistors cannot be stuffed at the same time.

VTRIG is a resistor based voltage divider circuit. It is intended to lower the voltage rail for the VTRIG (input pin to this sensor IC) to desirable & safe voltage level.

See here for an online calculator.
https://ohmslawcalculator.com/voltag...der-calculator

Revised without my typos --- the voltage is fine at this pin.

[Bartoloni]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

ok thank you mon2!

[mon2]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

Wish to mention that the SHDN# pin is shared across the logic board.

From your reading of ~5 volts means that no one camped on this common signal line is requesting for a shut down.

The fault is somewhere else. Perhaps an excessive current draw and that power rail is removing its downstream voltage? Probably this is an issue.

After the board shuts off -> check the voltage to ground of each large coil (probably grey in color).

No experience with this but perhaps even a BIOS or EC firmware fault.

Do check if the CPU is getting too hot or not. Ample heatsink and heatsink compound ?

[Bartoloni]

Re: Bypass Sony SVE151E11M thermal protection? (schematics provided)

every voltage is correct when the laptop is ON (also the hard disk is working) the thermal camera is not showing anything hot (just the 2 mosfet on 1.8V are at 37°C ) no coils spotted.