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 but it always turns off after ~10 seconds.
6) repressing power button doesn't work 9/10 times. If it does work you're lucky the laptops turns back on and stays on (Windows boots)
Already reprogrammed bios chip (UC3) with a different one from the internet. Has a completely different BIOS and EC version. Same result.
I immediately suggested the EC (super io chip) IT8226E-128.
Here are the measurements for all the SIO inputs:
What I can see:
The battery charges when the charger is plugged in seen from the voltage going to the battery that increases.
The battery indicator light is controlled by the super io chip. The indicator light only works when the laptop is on (in that 10 second window).
When the laptop doesn't respond to the power button the charger indicator light also doesn't work.
Now my question is do you guys have any other suggestions where to look?
Is there a way to bypass the SIO chip to validate it is in fact the SIO chip?
Is this common behaviour for a bad SIO chip?
I've never replaced a SIO chip and I don't really like the pin pitch.
I read that I can just replace the chip with a unprogrammed blank one (maybe not even LENOVO text on the ic?). How does that work?
The SIO is just a microcontroller to my eyes with some fancy stuff in it. How can a laptop power on on a blank SIO?
Curious to your guys reactions. Lets see what you know 😀
Attached schematics and board layout. [MOD EDIT] Link to schematic/boardview https://www.badcaps.net/forum/troubl...64#post1768664
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 but it always turns off after ~10 seconds.
6) repressing power button doesn't work 9/10 times. If it does work you're lucky the laptops turns back on and stays on (Windows boots)
Already reprogrammed bios chip (UC3) with a different one from the internet. Has a completely different BIOS and EC version. Same result.
I immediately suggested the EC (super io chip) IT8226E-128.
Here are the measurements for all the SIO inputs:
| PIN | OK? | Comment |
| VCORE | Y | 1.9v. Seems ok |
| VCC | Y | 0v +3VS. Turns on from SUSP# trigger from +3VALW rail. Seems normal |
| VSTB | Y | 3.3v |
| VFSPI | Y | 3.3v |
| AVCC | Y | 3.3v |
| CLK_PCI_EC | Y | 0v. Is generated by PCH. Seems ok? |
| PLT_RST# | Y | 0v. Is generated by PCH. Seems ok? |
| ON/OFF | Y | ON/OFF button input active low |
| PECI_EC | Generated by PCH. | |
| NOVO# | Y | Novo button input active low |
| VCCIO_PG | Y | No stuff. PU901 is not provided. Q3 makes VCCIO so no PG available. |
| NTC_V1_GPU | Y | ~2.8v. Seems normal, drops lower when getting hot. |
| NTC_V1_CPU | Y | ~2.8v. Seems normal, drops lower when getting hot. |
| BATT_TEMP | Y | 0.3v when batt connected. Otherwise 3.3v. Assumed good. |
| BATT_I | ? | 0v even with batt connected. |
| ENBKL | Y | Noisy 0v. Generated by PCH. Assumed good seems to not be relevant. |
| ADP_I | Y | 0v. Seems not relevant. |
| ADAPTER_ID | Y | 2.4v. Assumed good? |
| NTC_V3_DIMM | Y | Seems normal, drops lower when getting hot. |
| CPU_PWRGD | Y | Comes on later when power is already provided. Assumed good. |
| MAINPWON | Y | No stuff. PD601 not available |
| LID_SW# | Y | Lid closed = LOW. Lid open = HIGH |
| PM_SLP_S4# | Y | Goes high when power on. Generated by PCH. Seems to always be low when power off. Assumed good. |
| SUSWARN# | Y | Goes high when power on. Generated by PCH. Seems to always be low when power off. Assumed good. |
| PM_SLP_S3# | Y | Goes high when power on. Generated by PCH. Seems to always be low when power off. Assumed good. |
| EC_FAN2_SPEED | Y | FAN speed from FAN header. Not relevant. |
| EC_FAN1_SPEED | Y | FAN speed from FAN header. Not relevant. |
The battery charges when the charger is plugged in seen from the voltage going to the battery that increases.
The battery indicator light is controlled by the super io chip. The indicator light only works when the laptop is on (in that 10 second window).
When the laptop doesn't respond to the power button the charger indicator light also doesn't work.
Now my question is do you guys have any other suggestions where to look?
Is there a way to bypass the SIO chip to validate it is in fact the SIO chip?
Is this common behaviour for a bad SIO chip?
I've never replaced a SIO chip and I don't really like the pin pitch.
I read that I can just replace the chip with a unprogrammed blank one (maybe not even LENOVO text on the ic?). How does that work?
The SIO is just a microcontroller to my eyes with some fancy stuff in it. How can a laptop power on on a blank SIO?
Curious to your guys reactions. Lets see what you know 😀
Attached schematics and board layout. [MOD EDIT] Link to schematic/boardview https://www.badcaps.net/forum/troubl...64#post1768664
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