acer aspire 5942g LP5511-P mobo problem

[jopapadogr]

Hi all

i recently bought a used and broken acer aspire 5942g mobo (LP5511-P) from an e-shop and i noticed the following things:
1) With mobo only (no cpu, no ram, no interfaces, no lcd screen etc) i put the power jack and the mobo lights the 3 leds. Then i push the power btn and it lights the rest 4 leds too.
2) I noticed that after a couple of seconds, the 7 above leds are going off and after a couple of seconds it goes on again in a endless loop sequence.
3) I put the FAN in the slot and it starts blowing air and after a couple of seconds it goes off again
4) I check the +3V and +5V signals and it looks ok
5) I also noticed that when it starts, all the signals +3VALW and +5VALW are on and off again in the same sequence as at step 2.
6) When i plug in the battery it goes on the same sequence loop (on then off)
7) With the battery only (no AC adapter) it goes on the same loop (on and then off)

Is it any walkthrough guide or other way to check this mobo?

TIA
PS I have the schematic diagram also

 

[iamkamalrandhawa]

Dear freind first put an cpu and then check again because some laptop motherboard's automatically shut off if they have no cpu.

 

[jopapadogr]

Yes i've already test it with cpu and ram too. The same loop again. I was affraid not to burn the cpu so after the 2nd loop i 've put it off again. I dont know the exact sequence to test the mobo. I know that in the first stage it gives only some of the voltages and in the next state give the others to prevent faults.

 

[iamkamalrandhawa]

ok first of all you have to check short circuit in motherboard and check is there any component is heated up or not.

Yes i've already test it with cpu and ram too. The same loop again. I was affraid not to burn the cpu so after the 2nd loop i 've put it off again. I dont know the exact sequence to test the mobo. I know that in the first stage it gives only some of the voltages and in the next state give the others to prevent faults.

- - - Updated - - -

and also check for north bridge and south bridge , are they heating up than normal. Remove all addon cards.

 

[jopapadogr]

Well my friend i finally found the fault. It is a broken CPU. I found a ***** to the top when i was try to clean the surface to put new silicone paste. I 've already bought a new mobo and now i'm looking for I7 720qm CPU.....:-(

 

[iamkamalrandhawa]

ok freind . enjoy the life's every moment. but i am confused it was broken CPU !!!

Well my friend i finally found the fault. It is a broken CPU. I found a ***** to the top when i was try to clean the surface to put new silicone paste. I 've already bought a new mobo and now i'm looking for I7 720qm CPU.....:-(

 

[jopapadogr]

After i change the mobo with a new one and puting a used but good CPU, i finaly save my laptop. I 'm happy because they asked me 450 euros for service and parts. I spend only 210 euros for the mobo and the CPU.