Help me remove shorting Compal LA- 5752p

[IamPritesh]

I had this laptop which had flickering screen but everything else was working fine.
I tried a new lvds cable and that is when things got even worse. now the laptop does not start at all.
If I remove the cpu, then it try to start though with leds glowing , fan moving and then shutting down obviously.
If I put the cpu back and plug in the ac adapter, i can hear a tick tick sound coming from the cpu ..
Upon checking I can see shorting in the 1.05VS line. PJ1 has shorting on the +1.05VS side.

I have DC power supply , multi meter and Hot air gun if that helps . Attached the schematic as well

[piernov]

Re: Help me remove shorting Compal LA- 5752p

What's the exact resistance to ground on +1.05VS?

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

Its 0.008

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

Tried with another CPU as well.. no luck.

[piernov]

Re: Help me remove shorting Compal LA- 5752p

Resistance in ohm, not diode mode.

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

Its 0.00 in ohms

[aanan]

Re: Help me remove shorting Compal LA- 5752p

remove cpu & check res also check q11 remove L25,L26 & check res.

[piernov]

Re: Help me remove shorting Compal LA- 5752p

Lots of stuff on +1.05VS, easiest is to inject 1V at 3 or 4A and check what gets hot, without CPU. First suspect: PCH.
But first you can remove PJ14 and check that the short is on +1.05VS and not +1.05VSP.

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

Its 0.02 ohms at PJ1 if I remove the CPU

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

PJ14 is not connected and its short only on one side ( +1.05VS )

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

remove cpu & check res also check q11 remove L25,L26 & check res.

Removing L25 and L26 has removed the tick tick sound when CPU is attached to the socket.
But now board does not even start without cpu ..no leds glowing, no 3 or 5 volt on the coils

[piernov]

Re: Help me remove shorting Compal LA- 5752p

Sorry misread the schematics, +1.05VS is obviously taken from +1.1V_VCCPP, not +1.05VSP…
Try to inject 1 volt on +1.05VS still.

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

Sorry misread the schematics, +1.05VS is obviously taken from +1.1V_VCCPP, not +1.05VSP…
Try to inject 1 volt on +1.05VS still.

The DC power supply does not show shorting after removing L25 and L26 , but there is no 5 volt or 3 Volt even without the CPU .
Have i messed it up ? Earlier I could atleast start the board without CPU ..
Please suggest

[piernov]

Re: Help me remove shorting Compal LA- 5752p

Check resistance on both pads of L25 and L26 to see if there is a short there.

[IamPritesh]

Re: Help me remove shorting Compal LA- 5752p

L25 and L26 has 0.00 ohms on side of the pad