Sony MBX 247 Laptop Dead. Need help ( Pics attached )

[IamPritesh]

Here I have this Sony laptop that is dead. Upon opening it saw SMD capacitor almost burnt . I did remove it and haven't replaced it yet. The board still not not start. I want to know is it essential to put a new one ? I have also flashed the bios chip with a new one and still nothing happens.

Also from what I have observed.. the bios chip ( Pin8 ) has around 1 volt..
The power button has around 1.5 volt..
5 volt and 3 volt Always is present though.

I have attached the two images .. 1 of the capacitor that was burnt and the other that produces the AC_OK signal and I want to learn how that works..


ADAPTER SECTION of THE IMAGE
PR187 has 19 V on one end and on the other end it is 0 volt. Is that normal ?

BURNT CAPACITOR IMAGE

PC 61 was burnt and short as well.



Thanks everyone for your time.

[techtiger]

test Voltage on KU1 SIO IC pin 115 +3VPCU
test Voltage on KU1 SIO IC pin 102 & 108
test Voltage on PL13 out put +3VPCU

[IamPritesh]

Originally Posted by techtiger

test Voltage on KU1 SIO IC pin 115 +3VPCU
test Voltage on KU1 SIO IC pin 102 & 108
test Voltage on PL13 out put +3VPCU

First of all thanks techtiger for helping me on this.

The readings are as follows :


KU1 SIO IC pin 115 +3VPCU = 3.3V
KU1 SIO IC pin 102 = 3.3 V
KU1 SIO IC pin 108 = Varies from 0.5 V to 1 Volt

PL13 output has 3.3 Volt.

Please guide me how to proceed.

[IamPritesh]

Also I am not sure where exactly is the Power switch connector (CON1) getting the voltage . I checked the schematic but could not find it. I can see voltage source for capslock, scroll and numlock though.

[techtiger]

Originally Posted by IamPritesh

Also I am not sure where exactly is the Power switch connector (CON1) getting the voltage . I checked the schematic but could not find it. I can see voltage source for capslock, scroll and numlock though.

power swith connect to CON1 pin 9 should be 3.3V NBSWON, remove the power button and test R107 for any short with multimeter after test pin 9 with out power button for voltage

[techtiger]

for the PR187 it is normal for me PQ35 is a N-Channel Dual Fet when pin 5 goes high pin 3 goes GND

[IamPritesh]

Originally Posted by techtiger

power swith connect to CON1 pin 9 should be 3.3V NBSWON, remove the power button and test R107 for any short with multimeter after test pin 9 with out power button for voltage

R107 has not shorting. The voltage is around 0.3 volt at R107

KU2 Pin 4 and Pin8 have 3.3 volt.

[techtiger]

test KU1 pin 108 with multimeter resertence with out power , did you test with out the power button ? test KU3 pin 7 & 8 for voltage

[IamPritesh]

Originally Posted by techtiger

in post #1 you have mention that the BIOS is getting 1V so now the Bios have 3.3V, test KU1 pin 108 with multimeter resertence with out power , did you test with out the power button ?

BIOS (U3) is still showing 1 volt on pin8
KU2 has 3 .3 volt on Pin 4 and pin 8

I will test the pin 108 resistance asap.

[techtiger]

Originally Posted by IamPritesh

BIOS (U3) is still showing 1 volt on pin8
KU2 has 3 .3 volt on Pin 4 and pin 8

I will test the pin 108 resistance asap.

We are having a Confucian with the bios in your mob you have two Bios IC KU3 is your 1st Bios 2nd PCH U3 this IC gets Power after pressing the power button

[IamPritesh]

Originally Posted by techtiger

We are having a Confucian with the bios in your mob you have two Bios IC KU3 is your 1st Bios 2nd PCH U3 this IC gets Power after pressing the power button

Sorry for the confusion.. KU3 location has no chip . Its empty.


Pin 108 of Io Chip resistance to ground is around 8K Ohms
using multi-meter.

Update : Just rechecked the schematics and it clearly says that KU3 is not mounted with an asterisk symbol.

[IamPritesh]

What should I do next ? Any suggestions will be appreciated.

[piernov]

Did you replace PC61 yet? I guess it's required, it's part of a voltage multiplier that generates 15VPCU.
15VPCU is required to drive the gate of Q1, the MOSFET switching +3V_S3 from +3V_S5.

After replacing PC61, make sure PD27 and PD28 are not shorted, and that PC62/PC66/PC69 aren't either.

[IamPritesh]

Originally Posted by piernov

Did you replace PC61 yet? I guess it's required, it's part of a voltage multiplier that generates 15VPCU.
15VPCU is required to drive the gate of Q1, the MOSFET switching +3V_S3 from +3V_S5.

After replacing PC61, make sure PD27 and PD28 are not shorted, and that PC62/PC66/PC69 aren't either.

Thanks piernov for you value able inputs. I am unable to find a replacement for 0.1U/25V cap. Does it need to be exactly the same capacitor ?

[techtiger]

Originally Posted by piernov

Did you replace PC61 yet? I guess it's required, it's part of a voltage multiplier that generates 15VPCU.
15VPCU is required to drive the gate of Q1, the MOSFET switching +3V_S3 from +3V_S5.

After replacing PC61, make sure PD27 and PD28 are not shorted, and that PC62/PC66/PC69 aren't either.

piernov why is NBSWON getting 1V & the Bios Chip pin8 1V ?

[techtiger]

Originally Posted by IamPritesh

Sorry for the confusion.. KU3 location has no chip . Its empty.


Pin 108 of Io Chip resistance to ground is around 8K Ohms
using multi-meter.

Update : Just rechecked the schematics and it clearly says that KU3 is not mounted with an asterisk symbol.

can you uplode PIC of that bios chip

[IamPritesh]

Originally Posted by techtiger

can you uplode PIC of that bios chip

There is no chip on KU3
Also does the capacitor need to be of the same value for pc61 ?

[on/off]

• +3V_SPI come from +3V_S5 via R61 (short pad), When PQ44 ON require trigger from RVCCD (approx 12V).
• S5_ON generated 15VPCU be RVCCD.
  
• Maybe bios not working had effect KBC not work well.

[techtiger]

Originally Posted by on/off

• +3V_SPI come from +3V_S5 via R61 (short pad), When PQ44 ON require trigger from RVCCD (approx 12V).
• S5_ON generated 15VPCU be RVCCD.
  
• Maybe bios not working had effect KBC not work well.

thanks ON/OFF got the point

[piernov]

Oh yeah didn't even see it was required for +3V_S5… on/off is right.
Yes capacitor should most likely be replaced with the same value. 0.1U/25V are pretty common though. Higher voltage rating will work as well but it'll not be easier to find a 50V rather than a 25V (and package may be too big).