I managed to find that caps PC7229 and PC7230 were shorted and removing them from the board removed the short. Reconnecting PJ7204 and powering it up with those caps removed it boots successfully....

Spent some time trying to find out what is shorting B+ to ground. Went through and disconnected jumps that connect directly to B+ PJ6001, PJ5701, PJ1010 and PJ7204 progressively looking for change and identified the short is within the PJ7204 area as with PJ7204 disconnected the short to ground on B+ is gone.

Plugging in the adapter with PJ7204 disconnected gives 20v at PR5425. Pressing the power button the power LED flashes (which is better than before as it was completely dead)....

Yes, it confuses me because it seems impossible if ACOK is dependent on 3VLP which is dependent on B+, obviously it worked before so there must be something I am missing.

CMSRC is essentially missing, it's measuring fluctuations around 0.02v like the 5678 of PQ5400 and ACDRV.

I just checked resistance to ground at PR5425 and it is 5.6 ohms, so it appears B+ has a short to ground somewhere. I guess I should stop focus on PQ5400 and PQ5401 and focus on finding the short to ground on B+....

PQ5400
123 -> 5678 3.7 mega ohm
123 -> 4 3.5 mega ohm

PQ5401
123 -> 5678 3.7 mega ohm
123 -> 4 3.8 mega ohm.

Yes, I am in Taiwan but as a foreigner I don't always know where to get things and also being new to hardware it will be more the skills and equipment to do any replacement.

ACDRV is measuring practically zero. pins 5678 of PQ5400 is adapter voltage.
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Should I expect that the mosfets are on and B+ is present even if ACOK is low (as my understanding that ACOK is dependent on 3VL/P which is dependent...

Machine won't power on, no power led, no fan spin, completely dead.

Checked PQ5400 - AONS32314 and pins 5,6,7,8 are 20v (AC adaptor voltage) but pins 1, 2, 3, 4 are 0v.

Following Gate Pin 4 to PU5400 - BQ24780SRUYR.

VCC 20v
ACDET 2.8v
ACDRV 0v (goes to pin 4 gate of AONS32314).
ACOK 0v
REGN 6v

According to datasheet, conditions are correct for ACOK to be high but it is not.

Tracing ACOK it's connected to ACIN which is connected to a pin GPB0 of IT8227 but also shown as connected to +3VL via a 100k resistor...

Hi

I'm Michael.

Software Engineer that is trying to get into hardware repair.

Looking to start repairing a few laptops I have gained over the years that have issues.

Thanks