Technical Support Dell Alienware 17 R3 - LA-C912P Motherboard repair - 7 Beeps

[Mike Gou]

Hello.
I am having a disappointing motherboard repair with this laptop and I need your help.
This came in with water damage, doing absolutely nothing, and had almost all standby voltages shorted. I have already replaced all those shorted components:
-UE5 SIO KB9022QD - Programmed spare one, when replaced, 3.3v short got out
-PQ102 MDV1525URH
-U17 AOZ1331
-UE1 C8051F383-GQ
-PU800 SY8032ABC
-UI2 SY6288D20AAC
-PU508 RT6220AHGQUF 7P=
-PU100 TPS51225CRUKR
-PU300 TPS51212DSCR

Now, I get all the standby voltages, it turns on BUT with no lights and image. Fans spin for 5 sec then off, then again on and off until after 30 seconds where it beeps 7 times. Google shows 7 beeps is a CPU issue (FYI, CPU gets hot)
The weird thing I see is with PL509 (+VCCIOP) which gives 0v when I press the power button and has 0ohm resistance.
When PJP505 gets open-disengaged, PL509 has 0.9v.

Can you please check the schematics and boardview attached and see if that means that the CPU chip is dead for sure?
I don't know how to continue, I cannot fully understand the power sequence from this schematics. If the CPU needs replacement it will be a no fix unfortunately.

Any help would be appreciated! Thanks!

 

[Ahmad Safari]

Hello
For the ohm check, the voltage must be discharged.
If the ohm is zero, it is likely that the processor is damaged.
According to the table on page 56 of the schematic, this voltage should be produced when the enabler comes on, but because a connection has been detected, this voltage is not produced.

 

[Mike Gou]

The 0ohms is while discharged, unfortunately, measured with analog and digital multimeter. Let me note that the coil PL509 is 0.19v when PJP505 is connected, when disconnected 0.9-1.0v like I said in the first post, and PL508 +VCCSA is 1.1V.
I did not quite understand what you mean when you say "but because a connection has been detected, this voltage is not produced." Which connection you mean and which voltage?
Thank you.

 

[Ahmad Safari]

The 0ohms is while discharged, unfortunately, measured with analog and digital multimeter. Let me note that the coil PL509 is 0.19v when PJP505 is connected, when disconnected 0.9-1.0v like I said in the first post, and PL508 +VCCSA is 1.1V.
I did not quite understand what you mean when you say "but because a connection has been detected, this voltage is not produced." Which connection you mean and which voltage?
Thank you.

I use Google for translation and the wording is slightly different.
In short, you have a problem with this voltage, which indicates a failure in the processor.