• HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power

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#1 HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 28 November 2024, 21:03
Ho questo Pc HP ProBook 450-G2 che quando inserisco alimentatore il led bianco lampeggia di continuo e veloce tra bianco e ambra, lampeggia anche il led bianco nel tasto accensione, le tensioni 3.3 e 5 v. sono presenti, ho notato che la tensione VIN da 19.5 va in loop e scende fino a 13 volt, sulla scheda non ho notato corti, cosa posso controllare?.

Sul pin63 del KBC sono presenti 3 v e scende a zero in loop, quando scollego il ponticello PJP303 smette di andare in loop, la tensione VIN da 19.5 risulta stabile e pin63 del KBC 3 v assente.

Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


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#3 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 29 November 2024, 13:03
Machine wrote:Measure the resistance to ground of PJP303.

320 kohm.

#5 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 30 November 2024, 16:38
Machine wrote:With PJP303 closed on pin 63 of the kbc, is the voltage stable?


No pulsa 3 v. e scende a 0 v.

#6 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by Vogelek23 1 December 2024, 02:32
Disconnect all power (power supply, battery, RTC battery), short JCMOS1 pads for 5 seconds, then measure the resistance on pin 1 of DC1 diode (SOT323). Next, connect the power supply and measure the voltage to ground on pin 6 of PU102 charger chip. PJP303 jumper should be closed all of the time.

#7 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 1 December 2024, 16:59
Vogelek23 wrote:Scollegare tutta l'alimentazione (alimentatore, batteria, batteria RTC), cortocircuitare i pad JCMOS1 per 5 secondi, quindi misurare la resistenza sul pin 1 del diodo DC1 (SOT323). Successivamente, collegare l'alimentatore e misurare la tensione a terra sul pin 6 del chip del caricabatterie PU102. Il ponticello PJP303 deve essere sempre chiuso.


DC1 PIN 1: 43 Ohm.
PU102 PIN6: 2.66 Volt.

#8 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by Vogelek23 1 December 2024, 20:47
Desolder capacitors: CC6, CC39, C188 and C179 (it is quite enough to move them along so they are soldered just with single pin at one pad) and re-measure the resistance to ground on pin 1 of DC1 diode (correct pin count below).
Image

#9 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 1 December 2024, 20:57
Vogelek23 wrote:del diodo DC1


DC1 PIN 1: sempre 43 Ohm, questo comunica con il KBC oltre al BGA intel ma la CPU ho già provato a dissaldarla..

#10 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power  [SOLVED]


by Vogelek23 1 December 2024, 21:02
Lift pin 68 of KBC and check if you still have 43Ω to ground at pin 1 of DC1 diode.

#11 Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


by leonemax81 3 December 2024, 16:48
Vogelek23 wrote:Lift pin 68 of KBC and check if you still have 43Ω to ground at pin 1 of DC1 diode.


solved by replacing the KBC, thanks for the help.

Re: HP ProBook 450-G2 LA-B181P ZPL40/ZPL50/ZPL70 No power


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