Re: HP Pavilion Laptop Motherboard Not Starting Up DA0R53MB6E1
Check the Resistance to GND of the Enables and the outputs (VREG3, VREG5, Phase1 and Phase2) around PU7. Maybe already something supsicious to measure there.
Anything else I can check?
PQ50, PQ53 pins 5/6/7/8 = 19.7v, while schematic says there should be 5v.
PQ51, PQ52 = no voltage
PL24, PL25 = no voltage
pr245, white resistor = 2.9v
resistance to gnd:
PL24, rising from 10 to 12 kOhm
PL25, falling from 12 to 9.5 kOhm
PC74 = 10 Ohm
Anything else I can check?
PQ50, PQ53 pins 5/6/7/8 = 19.7v, while schematic says there should be 5v.
PQ51, PQ52 = no voltage
PL24, PL25 = no voltage
pr245, white resistor = 2.9v
resistance to gnd:
PL24, rising from 10 to 12 kOhm
PL25, falling from 12 to 9.5 kOhm
PC74 = 10 Ohm
We have Multiple or another fault present here. Check resistance to GND of Pin16, too
One fault might be there or a burned PR110
The thing with PQ50 and PQ53 is your wrong interpretation of the Drain designation and missing understanding of how a buck converter works.
Re: HP Pavilion Laptop Motherboard Not Starting Up DA0R53MB6E1
VREG5 is shorted but first need to fix VIN of PU7. No point troubleshooting PU7 unless VIN is fixed. PQ50/53-@sephiroth has already highlighted your misunderstanding-its correct at 19V. Do follow his suggestions and check resistance to GND on PR124-any pin. PR124 is located just after dc-in mosfets.
Re: HP Pavilion Laptop Motherboard Not Starting Up DA0R53MB6E1
PR 110 resistance is 0.460 kOhm
Resistance PU7 pin 16 to the ground is not stable, during the measure it fell from ~6 mOhm to 3 mOhm and keeps falling.
Same for PR124 - gnd, it falling from >10 mOhm to 3 mOhm and below, like if capasitor is loosing it's charge.
Anything else I can check? appreciate your answers
Re: HP Pavilion Laptop Motherboard Not Starting Up DA0R53MB6E1
PR10 is supposed to have 10Ohms internal resistance, so it has failed open. Likely caused by a bad PU7. For VREG5 you could inject 1V and see whether PU7 is getting hot or something else. Should be enough proof then to finally remove it afterwards.
Re: HP Pavilion Laptop Motherboard Not Starting Up DA0R53MB6E1
Yes, replace PR10 as suggested with rated value and then remove PU7 from the board(dont put power while PU7 is removed). Check resistance on VREG5 again after removing PU7.
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