Good afternoon all.
I have a customers HP 840 G1 with a 6050A2559101-MB-A03 mainboard.
Symtoms are, plug in the charger, power LED gives a quick flash, press power, power/mute/ wifi LED's come on after approx 10 secs, they all stay on for about 5 sec's then laptop powers down. Initial inspection shows no liquid damage.
Thus far I have reflashed the BIOS and EC with the files supplied here:-https://www.badcaps.net/forum/showthread.php?t=55509 posts 6 & 8.
I have started to trouble shoot in case there is a short and found there is no power going past Q6012. Removed Q6012, tested for a short and it reads O.L resistance to ground on both sides, DIODE mode pins 1-3 are 0.5443v but pins 6-8 are 0.1833v which to me on a 19.5v line is to low. So I suspect a partial short on the 19.5v rail..... and thats where I am now stuck.
I know I will get b*llocked for this but as a temp measure I jumped pins 1-3 with 6-8 on Q6012 just to get voltage down to Q6050 but still have the same results.
I also followed what was listed to be tested on this thread
https://www.badcaps.net/forum/showth...2559101-mb-a03
and got these results:
SIO Pin 74= 3.59v Pin 84= 3.25v
Pins 85=0
pins 38=0.4v
pins 81=0
pins 73 = 0.365v not pressed 0.007 pressed
pins 4-0
Resistance to ground L6750 = 29 ohms L6600= 177 ohms.
5v is correct tested on L6150
3.40v is on L6100.
What I have also noticed the current sense resistor which i belive is R6000 is reading 4.43 ohms in circuit and 3.2ohms out of circuit, the schematic shows it as being 0.01 ohms. the marking on the resistor is 10 and when I checked it is a 10 ohm resistor.
Just to add, on the second post its mentioned about the PCH. The PCH is not warming up when I get the 5 secs of power but the CPU does show a quick increase of heat under a themal camera.
I have attached the schematic I am using just in case someone needs it for reference.
Any help is greafully received...
I have a customers HP 840 G1 with a 6050A2559101-MB-A03 mainboard.
Symtoms are, plug in the charger, power LED gives a quick flash, press power, power/mute/ wifi LED's come on after approx 10 secs, they all stay on for about 5 sec's then laptop powers down. Initial inspection shows no liquid damage.
Thus far I have reflashed the BIOS and EC with the files supplied here:-https://www.badcaps.net/forum/showthread.php?t=55509 posts 6 & 8.
I have started to trouble shoot in case there is a short and found there is no power going past Q6012. Removed Q6012, tested for a short and it reads O.L resistance to ground on both sides, DIODE mode pins 1-3 are 0.5443v but pins 6-8 are 0.1833v which to me on a 19.5v line is to low. So I suspect a partial short on the 19.5v rail..... and thats where I am now stuck.
I know I will get b*llocked for this but as a temp measure I jumped pins 1-3 with 6-8 on Q6012 just to get voltage down to Q6050 but still have the same results.
I also followed what was listed to be tested on this thread
https://www.badcaps.net/forum/showth...2559101-mb-a03
and got these results:
SIO Pin 74= 3.59v Pin 84= 3.25v
Pins 85=0
pins 38=0.4v
pins 81=0
pins 73 = 0.365v not pressed 0.007 pressed
pins 4-0
Resistance to ground L6750 = 29 ohms L6600= 177 ohms.
5v is correct tested on L6150
3.40v is on L6100.
What I have also noticed the current sense resistor which i belive is R6000 is reading 4.43 ohms in circuit and 3.2ohms out of circuit, the schematic shows it as being 0.01 ohms. the marking on the resistor is 10 and when I checked it is a 10 ohm resistor.
Just to add, on the second post its mentioned about the PCH. The PCH is not warming up when I get the 5 secs of power but the CPU does show a quick increase of heat under a themal camera.
I have attached the schematic I am using just in case someone needs it for reference.
Any help is greafully received...
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