c660 la-6841p no power ic heat up

[doctormasry]

hi friends
i get laptop topshiba c660 pwwaa la-6841p no power
i check PU330 is heat up i changed it 4 times no new always heat up quickly
i check pQ331 . pQ332 . pQ351 and pQ352 good
change io ene 3 time same problem
after i connected adaptor pin 16 in pu330 be short for 30 second
and after 30 sec be good no short
pin 17 in pu330 ( VERGE5 ) is always short
I REMOVE IC FOUND PIN17 SHORT TOO
ANY HELP PLEASE

[mon2]

Re: c660 la-6841p no power ic heat up

Is PU330 still heating up ?

Remove all power. Meter in resistance mode (2k scale is ok).

Check the resistance to ground @ inductor PL332, pin # 1. Red meter probe on pin #1; Black meter probe on ground (shield is ok).

Repeat the same test @ inductor PL352, pin # 2.

Post your measurements. Checking for a low resistance which will likely indicate a shorted cap on the rail.

Also be sure of your soldering of this part -> flux it well and hot air till the part starts to swim on the SMD PCB pads. Then gently nudge the corners of this part till it moves away and then should bounce back, naturally. Repeat this 2-3 times and this should allow for a proper bonding of the solder pads and can be used to remove solder shorts under the device. You are making the IC 'dance' like Louis says in his videos on youtube.

[doctormasry]

Re: c660 la-6841p no power ic heat up

Is PU330 still heating up ?

Remove all power. Meter in resistance mode (2k scale is ok).

Check the resistance to ground @ inductor PL332, pin # 1. Red meter probe on pin #1; Black meter probe on ground (shield is ok).

Repeat the same test @ inductor PL352, pin # 2.

Post your measurements. Checking for a low resistance which will likely indicate a shorted cap on the rail.

Also be sure of your soldering of this part -> flux it well and hot air till the part starts to swim on the SMD PCB pads. Then gently nudge the corners of this part till it moves away and then should bounce back, naturally. Repeat this 2-3 times and this should allow for a proper bonding of the solder pads and can be used to remove solder shorts under the device. You are making the IC 'dance' like Louis says in his videos on youtube.

thanks for replay pro
i thest all cap and res on motherboard no short found
pin 17 in pu330 ( VERGE5) still short
pu330 heating up no new
pl332 is 250 ohm
pl352 254 ohm
just pl402 is 16 ohm and short

[mon2]

Re: c660 la-6841p no power ic heat up

PL402 is a low voltage rail at +1v05 so the low resistance reading is acceptable and not considered to be a short.

Still concerned about PU330.

Remove all power, meter in resistance mode (2k scale).

What is the resistance to ground of pin 17, PU330 ?

Desolder one side of PL332 inductor. Then check the resistance to ground of each side of this inductor.

What is the resistance to ground on PL332, pin # 1? Pin #2 ?

Do not power up with parts removed.

Do the same testing with one leg of PL352 lifted. If easier, remove these coils off the logic board.

To me, the resistance to ground for both of these rails is low and indicates a possibility of a shorted cap.

Post all of your measurements.