Hp 255 +5VA Coil shorted

[gcomputers]

Hi im working with this machine , the costumers say the problem has occurred from bad universal charger.
Led of charge is on 3.3v on power button present but not power.
I have check it and the 5v coil when i plug charge go on short with GND.
Measured TPS51123 :
vin 19v
vreg3 3.3v
vreg5 5v
trip1, trip2 0.7v
NOW
DRVH1 is shorted
DRVL1 is shorted
Pin 2 of L308 is shorted when i plug adapter only .
Replaced tps51123
replaced q317 also checked p309 and the same problem .
Any suggestion?

[rtstorm]

Re: Hp 255 +5VA Coil shorted

How can you tell that pin2 of L308 is shorted when adapter is pluged? Did you measure resistance while power was on board?

[gcomputers]

Re: Hp 255 +5VA Coil shorted

How can you tell that pin2 of L308 is shorted when adapter is pluged? Did you measure resistance while power was on board?

Thanks for your reply.
The consume of current is normal also charge the battery .
With adapter on it i measured L308 have 8 ohm, L307 190 ohm.
I have removed L308 and from pin2 of L308 to pin1 of PAD 306 i have short with ground please see my pictures .
Sorry for my english.

[highpulse]

Re: Hp 255 +5VA Coil shorted

you can't make measurement to gnd with power on , specially fets or coils :P or else they all will going to say they are all shorted .

[highpulse]

Re: Hp 255 +5VA Coil shorted

best way to do that is simple , remove coilof 5 vawl , the injecct 5 volts on the pad itself , and see what is gettng hot , what is getting hot , simple remove and replace , but before replacing , chek the pns of the warming component to see if there is no short there as well .

[gcomputers]

Re: Hp 255 +5VA Coil shorted

best way to do that is simple , remove coilof 5 vawl , the injecct 5 volts on the pad itself , and see what is gettng hot , what is getting hot , simple remove and replace , but before replacing , chek the pns of the warming component to see if there is no short there as well .

thanks Highpulse.
i have tried this method yesterday, i have inject power with PSU 5v on shorted pin 2 of L308 but it warms slowly TPS51123 replaced again this chip with new one but the same short of 5v.
do you think i have to inject power on pin2 or pin1 of L308?

[highpulse]

Re: Hp 255 +5VA Coil shorted

ohh forgot to mention !!! lift coil l308 and inject on the pad :P

[gcomputers]

Re: Hp 255 +5VA Coil shorted

ohh forgot to mention !!! lift coil l308 and inject on the pad :P

just tried removed coil and inject on PAD 5v 1a and getting hot TPS51123. replaced 2 time this chip with new.
??????????

This chip not have OUTPUT (DRVH1 is shorted when i connect adapter) .

[gcomputers]

Re: Hp 255 +5VA Coil shorted

any suggestion ..........