Well a reflow of the super IO chip resolved the issue.
So either it was a bad solder joint or the chip is going bad. I'll see long term.
Thanks for the help!

It does seem like it. Any other ideas?
My guess is still at the SIO chip. Still don't understand how a blank Lenovo chip could work. A blank microcontroller doesn't do anything.
Is a Lenovo SIO chip loading it's firmware directly from SPI on power? If so I should be able to see SPI activity when I apply power....

I might have jumped to the SIO too soon.
01)
DC-in fets diode measurements are all good (PQ201, PQ202, PQ203) and 20v reaches PR201 and 12v reaches PR213 (batt removed).
If they didn't work the laptop wouldn't power on on charger only.
02) [TABLE="border: 1, cellpadding: 1, width: 500"]
[TR]
[TD]COIL[/TD]
[TD]RAIL[/TD]
[TD]RESISTANCE[/TD]
[TD]DIODE measurement[/TD]
[/TR]
[TR]
[TD]PL1401[/TD]
[TD]+1.2V_P[/TD]
[TD]27 ohm[/TD]
[TD]0.029[/TD]
[/TR]...

Hello,

I've repaired a few laptops in my life but this time my own laptop died😂.
Funny enough this one is a bit tough on me.
It doesn't turn on (most of the time).
Model: Lenovo y520-15ikbm (NM-391).

The only way to make it turn on is:
1) unplug battery + charger + rtc (seems irrelevant)
2) wait a minute
3) plug battery/charger in
4) on charger plugin, laptop turns on by itself. On battery plugin you have to press power button. Sometimes nothing happens and you have to try again.
5) when it turns on it also displays POST...