Sony Vaio VPC-SB26FG cannot power on

[degebe2006]

Re: Sony Vaio VPC-SB26FG cannot power on

Hi guys!
I have just registered to share a bit of my experience with this mobo.
I had no power at all on this laptop (current draw was 0.01A when connecting the power adapter to the laptop). BTW, I am using a very convenient chinese cheap power meter to see what happens to the laptops when I connect them: http://www.ebay.com/itm/261219652805 .

I had the black connectors (in yellow rectangles) on the mobo shorted with each other and to the ground. Therefore, the power daughter board MBX-458 did not provide 19V to the shorted circuit.

Then I soldered regulated power supply terminals to the points shown GREEN. The voltage was set to 1.5V, the current to 3A. The capacitor in a RED rectangle became hot immediately. So, it was shorted to the ground. After I have removed it, all the shorts with black (6-pin and 10-pin) connectors went away. The cap was replaced by a compatible 10uF/25V ceramic cap, and laptop turned on, was assembled and passed to the customer.

Of course, in your case this can be ANY other cap or semiconductor, but the main method is the same: apply safe voltage (lower than the intended voltage for the shorted circuit) to the shorted circuit and slowly raise the current while controlling the temperature of the board (with your hands or using any pyrometer).

Good luck, colleagues, and successful repairs to you all! :-)

hi, How measure in mosfet R460 and mosfet r158, in this picture, thanks!!

[ageman]

Re: Sony Vaio VPC-SB26FG cannot power on

Guys

would anybody know the values of the 3 capacitors in the red box please.

Regards
Adrian

[Younso]

Re: Sony Vaio VPC-SB26FG cannot power on

Thank you

[mon2]

Re: Sony Vaio VPC-SB26FG cannot power on

@ageman - are these caps missing or deemed to be defective ?

Very likely they are bulk caps and from a distance look to be 0805 in size. Probably each are the same capacitance and being in parallel, they add together to filter that rail.

What are the markings on the IC that is south in your picture ? That component is probably creating the power rail with these caps being downstream. You can probably review a reference schematic for this IC to understand which caps are present on this logic board.

You can consider to remove one of the other caps that appear to be the same -> measure the capacitance and use the same for your cluster of caps. The voltage rating can be the highest you can find for the 0805 size but doubt that you are facing a voltage rail > 6 volts here. Post the SMD markings of the IC.

[ageman]

Re: Sony Vaio VPC-SB26FG cannot power on

Hi mon2

The caps were removed as the last one I removed was shorted. I measured the other 2 but they were 20uF which looking at the schematic, could not find any that value.
The IC is SN608098. See photo

Regards
Adrian

[mon2]

Re: Sony Vaio VPC-SB26FG cannot power on

Feel free to use 22 uf which is a very common part value for ceramic caps. We use them all the time in product builds.

[NBMSCH]

Re: Sony Vaio VPC-SB26FG cannot power on

hi everyone, I'm new in here and I have a VPCSA with the same power on problem...
what happened is that my laptop got overheated and shutdown
and after that it won't power on anymore...

does anyone knows what happened exactly?
please help me, and if you have any suggestion what should I do?
thank you very much!