Samsung NP350V5C laptop repair

[M.Joshi]

Hello all,

I am trying to repair the above Samsung laptop which just produces a series
of clicks when you press the power button? I have tried powering up without
the battery and removing any residual capacitor charge by depressing the
power button for 1 minute with neither the battery nor the AC adaptor connected.

The battery seems to be charging which indicates that the main 19V input
rail is functional.

Looking at the LA-8862P PCB schematic for the laptop, I cannot seem to work
out what the B+ voltage rail is and where it is generated?

Also, there is mention of a TPS51125 in the Power Tree block diagram but
it does not appear in any of the circuit schematics later on?

Any pointers would be much appreciated.

Thanks.

[Ken]

You may well have a problem that requires opening up the laptop, but I
would try another power supply before doing that. I have seen many
laptop that fail due to lack of current when under load. In fact I
purchased one for parts that the owner said would not power up, but all
it needed was a power supply. It has been working fine for over two
years now.

[M.Joshi]

Hello Ken,

The above tests were carried out with the main PCB removed from the laptop
and a known working AC adapter from another similar laptop.

The series of clicks seem to be emitted from both the left and right speakers
for two cycles then stop until the power button is depressed again.

Thanks.