How confident are you with the charger IC replacement ? My usual suggestion is to flux the part well and reflow it with low air pressure in a circle till the part swims into place.
Use the gentle nudge of the tweezers when the solder is in liquid form to make the part 'dance'. The part should push away and naturally bounce back onto the pads. Never push too hard else the pads can be ripped off the PCB.
How confident are you with the charger IC replacement ? My usual suggestion is to flux the part well and reflow it with low air pressure in a circle till the part swims into place.
Use the gentle nudge of the tweezers when the solder is in liquid form to make the part 'dance'. The part should push away and naturally bounce back onto the pads. Never push too hard else the pads can be ripped off the PCB.
That is normally how I do reflows as well, and I clean it up with my soldering tip afterwards, got some pics if you want to take a look.
Maybe the center ground pad is not making it to the PCB surface ? Usually we use tweezers to push down to squish the IC a bit to force the connection. Just be careful to not let the IC slide. Otherwise, very nice soldering of the QFN packaged device.
Just know from being on the XMOS forum - their audio ICs had this as a #1 issue - key clients of their silicon could not get their protos working. Each time, it was the CENTER pad that was not mating with the PCB surface.
Maybe the center ground pad is not making it to the PCB surface ? Usually we use tweezers to push down to squish the IC a bit to force the connection. Just be careful to not let the IC slide. Otherwise, very nice soldering of the QFN packaged device.
Just know from being on the XMOS forum - their audio ICs had this as a #1 issue - key clients of their silicon could not get their protos working. Each time, it was the CENTER pad that was not mating with the PCB surface.
I can give it a reflow again, but I already pushed down when soldering it the first time.
yOU DIDNT MENTIONED VOLTAGE ON ACN/ACP pins. I think its zero on pin1-2-3. In other words, voltage is not paasing out from dc-in mosfets. Have you checked them for short??
yOU DIDNT MENTIONED VOLTAGE ON ACN/ACP pins. I think its zero on pin1-2-3. In other words, voltage is not paasing out from dc-in mosfets. Have you checked them for short??
Both ACN and ACP is at 4.2V
The second DC-IN mosfet only outputs that 4.2V, but resistance on those two mosfets checks out fine according to user "mon2".
Do you have more replacement mosfets for the pair near the dc adapter connector?
Measure each while they are out of circuit to compare with the earlier measurements. Post the readings.
The concern is with the one reading of each where the value could not be measured. Is the reading so high for the meter scale or maybe an open circuit?
Mosfets are ESD sensitive so be sure to be grounded while working with them.
Do you have more replacement mosfets for the pair near the dc adapter connector?
Measure each while they are out of circuit to compare with the earlier measurements. Post the readings.
The concern is with the one reading of each where the value could not be measured. Is the reading so high for the meter scale or maybe an open circuit?
Mosfets are ESD sensitive so be sure to be grounded while working with them.
I have replacements for all mosfets yes.
I will desolder all and measure them off the board.
Did measurements on the new mosfets at the charging IC area, both on and off the board. I also did diode reading on S-D, and both mosfets came back with 0V when on board, but 0.4V when off the board, is that normal? Checked the mosfets at the DC-in area, and they both came back at 0.6V on the board.
Resoldered the charging IC area mosfets, and they again came back at 0V. Did a diode check on the pads underneath the mosfets, and they also came back at 0V, is that the culprit or?
OH yeah, and about the "non-readings" at the DC-in mosfets... turned the probes arund, and they gave me 4.6Mohm and 5Mohm then.
Before I desolder the DC-in mosfets, I just wanted to ask about this first, they do seem fine checking in diode mode, and I haven't touched them, and the laptop turned on fine, before I touched the charging IC area and surrounding mosfets, which is why I doubt they could be the culprit.
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