Acer VN7-793G missing 3D3V_RTC_AUX

[BalkanBoy]

Hi guys, I got strange issue with this laptop, I bought it as faulty, seller said it doesn't power on and it doesn't charge battery as well, he said like battery is dead or something, doesn't have to be true.

Anyway, I inspected motherboard and I figured out I don't have any voltage present on battery protection switch (SW1) and I got around 0.5V on reset switch. When I press power button 3V3 raises but nothing happens, no fans, no cpu or gpu voltage rises, no post.

I figured out I got no 3D3V_RTC_AUX voltage present, on diode D2501 I get around 0.7V on PIN1 and 0.5V on PIN3. When I remove diode I have 3.3V on PIN1, 3D3V_AUX_S5 is OK.

I changed diode but everything is same, something that uses 3D3V_RTC_AUX probably makes some mess but can't determine exactly what could be the issue.

Latest I tried is that I removed D2501 and hardwired PIN1 with PIN3, now motherboard starts and I got POST but can't leave it like that because RTC battery is totally isolated. Funny thing is I got stable 3.3V on 3D3V_RTC_AUX, doesn't drop without diode.

I attached photo of diode and schematics.
Motherboard code is Neptune_kls 16834-1m.

Any suggestion guys?

[mcplslg123]

Re: Acer VN7-793G missing 3D3V_RTC_AUX

Resistance to GND on pin1/3 of D2501
01.With diode soldered
02.With diode de-soldered.

Very likely its SOC Fault(PCH RTC section)

[BalkanBoy]

Re: Acer VN7-793G missing 3D3V_RTC_AUX

I've removed wire to take a measurements and soldered back the diode, now everything works like it should, I really don't get it. RTC battery is back again, it holds bios settings. Primary battery is charging as well, all drivers installed. I will do more tests but all looks good so far.


Seems like I did some kind of 'system shock' with that wire haha
Or I burned something that was making issue, very strange however.