No AC Adapter installed Dell 15 5570 LA-F115P

[mferna14]

Re: No AC Adapter installed Dell 15 5570 LA-F115P

Thanks for all the input @reformatt & @mcplslg123. @reformatt your input into this case seems to be very logical. I will not go step by step now. On the safe side I even replaced the DC-in jack just to exclude this part of the troubleshooting & using a Known good 100% original Dell Power adapter. Just wanted to confirm PSID should be present in standby mode for these motherboard?

[reformatt]

Re: No AC Adapter installed Dell 15 5570 LA-F115P

Just a backgrounder here so you entirely understand the logic.

Adaptor identification (PSID) is a small burst of data from the one wire chip inside the charger. These chips use parasitic power, which means power is derived from the data line itself. In this case, power is supplied from the host via the PSID line. These chips will immediately output their pre-programmed data when power is first applied, then stop. So if you put a scope on PSID, you will see that small burst of data when you initially plug the adaptor in, then it will stop. Power for PSID detection is provided by +3VALW in this case. I must stress that the +3.3V on this line is not an indication that PSID is working, it's just the power for the one wire circuit in the charger.

From a sequence point of view, the EC is not continually polling this line, as the PSID data is only present for a short time when the adaptor is first plugged in. So its only considered when a state change occurs with the charger (i.e. it goes from unplugged to plugged in). If the logic for adaptor presence is crook, then PSID is never considered as you don't get to that part of the sequence. This is supported by the fact that +3VALW is missing in S5 in standby, because that is controlled by the EC.

This design can use the barrel adaptor or USB C for system power, and switch accordingly. The design is somewhat complex, but my assumption is that the barrel adaptor would take precedence over USB C. You can check which one is being used by PWR_SELECT (high for barrel, low for USB C). How this is determined in the EC I'm not sure, but I would consider reviewing the DCIN_AC_DETECTOR post that @mon2 referred to in this thread. Review HW_ACAVIN_NB when adaptor is plugged/unplugged.

There are other lines to review, but I'd start off there. And also check your input FET's PQ3/PQ4, AC_OK, AC_B2B_ACOK etc as well.

[mferna14]

Re: No AC Adapter installed Dell 15 5570 LA-F115P

Thanks you so much for all the logical explaintion. really appreciate @reformatt.... Ok guys guess what. Just for fun sake I removed the ISL chip & wanted to put a new one. I searched in my donor boards & found none. Cleaned this chip thoroughly with alcohol & Cleaned all the solder pads on the MB & soldered it back to the motherboard. To my extreme past days fustration, all worked once again. Looks like dry solder somewhere, this is why AC detect was working in the start & then intermittent.. Now working like charm & thanks to all you guys help. Best help fourm I must say.

[mcplslg123]

Re: No AC Adapter installed Dell 15 5570 LA-F115P

Now confirm whether any voltage is present on PSID line in standby mode??

Keep your fingers crossed.The charging chip may be working 'coz heat is applied and it may fail again after 3-4 days.

[mferna14]

Re: No AC Adapter installed Dell 15 5570 LA-F115P

PSID 3.3V is present in Standby mode., I have ordered these ISL battery charge chips. Yes it might go bad any time. Thanks mcplslg123