Might be useful for someone else in future this one.
Unit was a HP 13-4102TU fitted with a DAY0DDMBAE0 Rev E motherboard. Board appears dead, no current drawn from ext PS. The DC jack power LED blinks on then off rapidly every second or so. The blink is so rapid you may even miss that it's there. Initially I was thinking it was an EC problem till I noticed those blinks (they're easy to miss). EC was getting 3.3V from the LDO output of PU11 and I could dump the EC contents with my SVOD programmer. So for me it was likely an issue coming from the BQ24780 battery controller side of things.
Output of the battery buck converter FET pairs PQ11/PQ8 had a short across PQ11 drain to source. Removed that FET, but short still present! PQ21 connects the battery to Vin when it's off charger (so it sits between Vin and the output of the choke PL14). What was fitted to the board was a AON6370. I didn't have that one, so used a AON6426 in it's place (higher drain rating anyway). I noticed that PR237 was missing afterwards so I think I knocked it off. Was 4K on the schematic, so I used a 3.9K and it seems to work fine when on battery only. Datasheet for the BQ controller says it's only to limit inrush current to the chip so I'd say that 100 ohms difference will be ok ;-)
Anyway, hope it helps someone since I get a lot of good help on this forum!
Unit was a HP 13-4102TU fitted with a DAY0DDMBAE0 Rev E motherboard. Board appears dead, no current drawn from ext PS. The DC jack power LED blinks on then off rapidly every second or so. The blink is so rapid you may even miss that it's there. Initially I was thinking it was an EC problem till I noticed those blinks (they're easy to miss). EC was getting 3.3V from the LDO output of PU11 and I could dump the EC contents with my SVOD programmer. So for me it was likely an issue coming from the BQ24780 battery controller side of things.
Output of the battery buck converter FET pairs PQ11/PQ8 had a short across PQ11 drain to source. Removed that FET, but short still present! PQ21 connects the battery to Vin when it's off charger (so it sits between Vin and the output of the choke PL14). What was fitted to the board was a AON6370. I didn't have that one, so used a AON6426 in it's place (higher drain rating anyway). I noticed that PR237 was missing afterwards so I think I knocked it off. Was 4K on the schematic, so I used a 3.9K and it seems to work fine when on battery only. Datasheet for the BQ controller says it's only to limit inrush current to the chip so I'd say that 100 ohms difference will be ok ;-)
Anyway, hope it helps someone since I get a lot of good help on this forum!
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