• HP Elitebook 840 nie uruchamia się

It is currently 14 December 2024, 07:39

HP Elitebook 840 nie uruchamia się

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#1 HP Elitebook 840 nie uruchamia się

by darole • 24 June 2024, 08:29
HP Elitebook 840 G1
MB: 6050A2560201-MB-A02
KBC: MEC1322-NU
CPU: SR1ED

Mam problematyczny przypadek laptopa HP Elitebook 840 G1. Po podłączeniu zasilania migają równocześnie dioda we włączniku i CapsLock.
Stwierdziłem że pływa mocno napięcia za tranzystorem Q6010 co może powodować miganie powyższych diod. Posprawdzałem półprzewodniki w układzie ładowarki i nie namierzyłem uszkodzonych elementów. Wymieniłem układ ładowarki BQ24736. Bez zmian.

Pomiary napięć:
Posiłkowałem się schematem ładowarki podobnego laptopa (840 G2 6050A2637901-MB-A02):
Image

BQ24736 (wiele napięć pływa):
1 17-19V
2 17-19V
3 17-19V
4 23-26V
5 0-1V
6 2,63V
7 0V
8 3,38V
9 3,38V
10 3,37V
11 0V
12 1-3V
13 1-3V
14 0V
15 0V
16 6V
17 5,8V
18 1-3V
19 1-3V
20 17-19V

Q6010
D 12,8-19,7V
S 19,68V
G 6-14V

Q6011
D 14-19V
S 12,8-19,7
G 0-19,7V

Q6012
D 1,3-3,9V
S 14-19V
G 12,9-19,7V

Mam też oscylogramy:
Q6010_G:
Image
Q6010_D:
Image
Q6011_G:
Image
Q6011_D:
Image
Q6012_G:
Image
Q6012_D:
Image

Te piki powtarzają się co 1,4s
Gdzie szukać przyczyny tych prób załączenia. Zwarć na dławikach nie namierzyłem.

Re: HP Elitebook 840 nie uruchamia się

by Google Adsense [BOT] • 24 June 2024, 08:29

#3 Re: HP Elitebook 840 nie uruchamia się

by darole • 25 June 2024, 05:30
Resistor R6018 is ok and it has 4,3k Ohm resistance. But there was a missing connection between R6018 and the 4 pin of BQ24736 (ACDRV). I corrected this with a thin wire, the oscillograms changed but the voltage peaks are still visible.

Q6011_G:
Image
Q6011_D:
Image

#5 Re: HP Elitebook 840 nie uruchamia się

by darole • 25 June 2024, 21:19
L6100 -> 14k -> 3,38V and oscillates slightly downwards
L6150 -> 23k -> 5,1V and oscillates slightly downwards
L6000 -> 50k -> 0,83V
L6200 -> 366 Ohm -> 0V
L6600 -> 80 Ohm -> 0V
L6350 -> 11,1k -> 0V
L6300 -> 3,1k -> 1,05V
L6450 -> 746 Ohm -> 1,28V
L400 -> 700 Ohm -> 0V
L2550 -> 3,8k -> 3,38V and oscillates slightly downwards

#7 Re: HP Elitebook 840 nie uruchamia się

by darole • 28 June 2024, 06:43
42 pin of KBC : 0 to 2,4V
Image

pin 2 of JACK6000 - LIMIT_SIGNAL: 0 to 2,3V

U6200. pins:
1 1,05V
15 3,9V to 19,9V
18 2,2V to 5V
20 2,2V to 5V
22 1,05V
24 0V
25 0V
26 2V
28 1,7V to 3,4V

When measuring the voltage on pin 42 of the KBC, I accidentally shorted pin 42 with pin 41 (on which the voltage also floats from 0V to 3.7V).
This causes the board to turn on with the correct voltages and corect image on DisplayPort output every time after holding it for a few seconds.

#9 Re: HP Elitebook 840 nie uruchamia się

by darole • 28 June 2024, 10:48
63 pin of KBC: oscillates from 0V to 3,44V

Q6009:
G: oscillates from 0V to 19,3V
Image
S : oscillates from 0V to 6,1v (most time) and even to 18,4V for a moment
Image
D : oscillates from 6V to 10V
Image

Q6013:
G: oscillates from 0V to 3,34V
Image
S: oscillates from 0V to 3,34V
Image
D: oscillates from 0V to 19,8V
Image

#11 Re: HP Elitebook 840 nie uruchamia się

by darole • 1 July 2024, 05:43
As I mentioned at the outset - when power is applied, the LED on the switch and CapsLock flash simultaneously.
Current: oscillates from 4,75mA to 12,58mA without pressing start button.
When I start the board by short-circuiting pins 41 and 42 of the KBC, the board draws a stable 460mA with a momentary drop to stable 12mA during a reboot.

Re: HP Elitebook 840 nie uruchamia się

by Google Adsense [BOT] • 1 July 2024, 05:43
 This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).
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