Asus X512DA - AMD Ryzen 5 3500U - No power

[mon2]

It depends on to whom the ACOK signal is mated. Highlight ACOK and locate the pull-up resistor on this signal line. If indeed the pull-up is to REGN (which is ~6v) then this is ok. Confirm the pull-up resistor is similar to the value showing in the BV file (guessing it will be ~10k or higher). This is ok.

This signal will be used by other logic to denote that the adapter voltage ok. Keep in mind that this is an open-drain / open-collector signal. That is, the charger IC will either drive this pin low (0v) if the adapter voltage is out of range OR release it to floating state if all is OK. At that time, the mandatory external pull-up resistor is used to park this floating signal line to the pull-up voltage of REGN (assuming). So all is normal here.

3VA_EC will most likely be from the local 3v_ALW LDO rail. Hunt around for such a regulator. This regulator will always be ON unless there is a fault with the EC. Do measure the resistance to ground of this missing 3VA_EC. If it is low, this may be a fault. Highlight this rail and you should be able to locate the LDO rail of interest.

[krayz]

It would seem I have found the issue: A 1M resistor PR8922 was blown. I replaced it and, to great joy, was greeted by the Asus loading screen. I'll test around some more to see if everything is in order.

[krayz]

Another problem emerged:

- there is a power led sequence, but i couldn't find the meaning: 1 long white blink, 1 short orange blink -> 4 times, then boot

- the laptop works while plugged in with battery disconnected.

- it also works while plugged in with battery connected, but here windows shows "Battery fully charged", which is highly unlikely. It turns off instantly when unplugging;

- it DOESN'T work on battery only

Here i found PQH8901 is giving me inconsistent resistance measurements and a S-D voltage drop measurement of 1,4V.

[pc_okay]

Hello again,

Thats good you don't give up! 😀

Review your entry mofset PQ8901/02 like you learn earlier.
And PQ8907.

[krayz]

Sometimes stubberness pays off

I checked PQ8901 (in the previous post i wrote incorrectly, voltage drop was 0,14V) off the board and it was OK, S-D voltage drop 0,5V and normal resistances. Then PQ8902 started having voltage drop S-D 0,14V. So i put PQ8901 back, since it was good. Not sure how to proceed.

[krayz]

Update with additional info:

- Now the laptop behaves like this:
-AC and battery plugged in -> Battery 0% and charging, but in reality it is not, constant 0%.
-AC only, battery unplugged -> "Battery fully charged" (??), and not charging.

- I can charge the battery with LabPSU. Checking with the multimeter DC mode, red on red, black on black, i'm not getting any reading. Checking the cells themselves, i get 3V on both of them.

- Plus pin of battery connector to GND when connected to AC shows ~0,86V

Also, the LED sequence isn't showing up anymore.

BTW, other than testing with a known good battery, is there any way to isolate the issue to the battery? I'm not too keen on gambling on buying a new battery only to find out it wasn't the issue...

[krayz]

I gambled and bought a new battery (traveled like 40 days 😅). It came partly charged and when i plugged it in, the laptop came on.

- If it's on AC, it shows the charging sign, but it does not charge.
- If i unplug the AC adapter, it stays on.

So now the only thing left to solve is the battery not charging issue. How would I go about this?