Hello!
I have this laptop on my bench, dead no power, no leds.
Checked the MB , and found 2 burned components with a hole on them, KBC and battery charger IC PU301 (BQ24781)
No liquid damage.
Replaced both components, still no power.
Found that +3VLP_EC is oscillating and +19VB same thing.
When I open JP2 to isolate, +3VLP is 3.3V and +19VB is 19V stable
No short in +3VLP_EC and all KBC pins measure ok. no shorts
I hear a clicking sound ,think it comes from the chipset, and this clicking sound is cycling matching the cycling consummation on the PSU, 2-3mA, 25mA,2-3mA and so on. Sometimes I see CC light blinking shortly.
Measured caps on the chipset, all values seem OK, nothing shorted.
Same thing around the chipset itself, all values seem OK, no shorted lines.
All coils OK, no shorts found also.
No voltages present, except in PL301 I have 0.21V (battery coil)
What do you guys think? Bad chipset?
Any other test or measurements I could do to confirm this?
KBC chip was not programmed, but I suppose if that was the issue, +3VEC would still be stable.
Let me know if you have other suggestions for this case.
Thank you!
I have this laptop on my bench, dead no power, no leds.
Checked the MB , and found 2 burned components with a hole on them, KBC and battery charger IC PU301 (BQ24781)
No liquid damage.
Replaced both components, still no power.
Found that +3VLP_EC is oscillating and +19VB same thing.
When I open JP2 to isolate, +3VLP is 3.3V and +19VB is 19V stable
No short in +3VLP_EC and all KBC pins measure ok. no shorts
I hear a clicking sound ,think it comes from the chipset, and this clicking sound is cycling matching the cycling consummation on the PSU, 2-3mA, 25mA,2-3mA and so on. Sometimes I see CC light blinking shortly.
Measured caps on the chipset, all values seem OK, nothing shorted.
Same thing around the chipset itself, all values seem OK, no shorted lines.
All coils OK, no shorts found also.
No voltages present, except in PL301 I have 0.21V (battery coil)
What do you guys think? Bad chipset?
Any other test or measurements I could do to confirm this?
KBC chip was not programmed, but I suppose if that was the issue, +3VEC would still be stable.
Let me know if you have other suggestions for this case.
Thank you!
Attached Files
.Ok remove LB1 and check +3VLP_EC again
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