Laptop Seems 'Dead' won't turn on

[Sadlercomfort]

Hello Guys,

I have a laptop I'm looking at for my friend. It doesn't show any life at all. You plug the adapter in and the battery light indicator doesn't show that it's charging. And when you try turn it on, nothing happens. I've tested the dc adapter and am getting the appropriate 19.5v so the adapter is fine.

I've tested inside the laptop to ensure the 19.5v is carried forward into the motherboard. That's fine.

There are no obvious signs of damage inside, I've removed the ram and turned it on.. that didn't work.

I've replaced the cmos battery, but that didn't work.

Really need help,

Ash

 

[Sadlercomfort]

vgn-nr38e laptop

 

[Gryd3]

This is going to be very difficult to troubleshoot and follow. Hopefully it is something simple. You have traced the 19.5V into the board, have you been able to identify any of the components this feeds? There should be additional voltage regulators present, hopefully the problem lies there.
These boards are multi-layered, so aside from having a sixth sense, or practice looking at these things, it may be time consuming identifying the components on the board.

 

[Sadlercomfort]

I've found it difficult following the trace on the board, I'm not sure which components regulate the supply.

 

[Gryd3]

Unfortunately, I can't spit out part numbers for you.
LM78XX series are common for low draw components, but the laptop may be using alternative methods to regulate the voltages required.

Is the main board in this model one unit, or does it have a smaller daughter-board for power?

 

[Thirantha]

Remove the battery and try to switch on the machine with charger plugged in.