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Old 12-20-2013, 07:11 AM   #41
michaeleangelo
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by orientalsniper
Hello, when you were repairing a MBX-458, why did you apply current to the cap in red box? And not the others?
Hi there!

The cap that is in the red box was faulty. But when I applied current to GREEN points, I did not know this yet.

The reason I applied current to these (GREEN) spots is that these are main GROUND and VIN (+) in points on this board. And when you apply current to the shorted cirquit, it starts to dissipate heat. The component that gets warm is most likely to be defective.

In my case it was the capacitor outline in red.
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Old 12-20-2013, 07:40 AM   #42
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by vaiohustler View Post
could guide me a little to find the faulty component
Why do you think you would get anything more than 0.01V on these pads without battery connected and with KBC (keyboard controller) disconnected (it is located on the MAIN board, MBX-238, and rules the charging process)?

The points you measure voltages at are battery "+" and "-" terminals, and there has to be no voltage (or close to none) without battery.

The point we discuss in this thread is that there is a short cirquit on the MAIN board (MBX-238) that causes CNX-458 to SHUT OFF the output if it detects overcurrent on any of the outgoing cirquits.

So, please measure the resistance between the green points on my photo. If it is close to zero, then apply regulated current supply to these points and check what elements do heat up.

Is there any reaction on the "power on" button?

Last edited by michaeleangelo; 12-20-2013 at 07:42 AM..
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Old 02-05-2014, 12:20 PM   #43
datom
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by michaeleangelo View Post
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! :-)
Thanks a lot! For me it was the one next to it.
It took me a while to find it, because it didn't really get hot, even with 6A. But as the cable already got warm, I simply tried first your broken one and then the one where I put current on --> Got it
It's back to life, Thank you man!
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Old 04-04-2014, 04:06 PM   #44
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by datom View Post
Thanks a lot! For me it was the one next to it.
It took me a while to find it, because it didn't really get hot, even with 6A. But as the cable already got warm, I simply tried first your broken one and then the one where I put current on --> Got it
It's back to life, Thank you man!
how could you solve this prob.. ? Thanks for you answer right now.. !
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Old 04-04-2014, 04:08 PM   #45
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by chat007 View Post
I swapped the motherboard and it's now working . Thanks for pointing out the problem is on the MB. When you are swapping the board, make sure the dip switches match.
swapped? change your mob with new one?
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Old 04-07-2014, 09:54 AM   #46
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Default Re: Sony Vaio VPC-SB26FG cannot power on

hi thanks a lot for your help
I have a sony vaio vpcsb1s1e
and it's dead not working at all
when i saw your reply about changing capacitor I found two capacitor with 0 ahm
"the capacitor in the red box and the one below it" and I replace them but it still dead so I need to ask and make my self sure about the capacitor if the 10uf 25v or not
and I need help for the next step what can I check or what I missed
is the bios need to charge again from usb port
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Old 04-07-2014, 10:00 AM   #47
osama31
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Talking Re: Sony Vaio VPC-SB26FG cannot power on

hi thanks a lot for your help
I have a sony vaio vpcsb1s1e
and it's dead not working at all
when i saw your reply about changing capacitor I found two capacitor with 0 ahm
"the capacitor in the red box and the one below it" and I replace them but it still dead so I need to ask and make my self sure about the capacitor if the 10uf 25v or not
and I need help for the next step what can I check or what I missed
is the bios need to charge again from usb port
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Old 04-08-2014, 12:48 AM   #48
lefos
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Default Re: Sony Vaio VPC-SB26FG cannot power on

hi there. Check also the caps next to the one you have changed. Also check in the small psu board under the stickers of the connectors for tiny fuses.
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Old 04-08-2014, 02:42 AM   #49
datom
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by oxgan View Post
how could you solve this prob.. ? Thanks for you answer right now.. !
I simply changed all of the 3 caps (10uF, 25V) to make sure it will last longer, maybe they didn't use 25V caps
For me there was nothing else to do
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Old 04-09-2014, 03:54 AM   #50
osama31
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Are the values ​​written on the image correct ???
What are the values ​​of capacitors located by the question marks???
Is it possible to give me a photo showing the names of the electronic items found on the main board to compare it with the existing maintenance manual???
sorry for my questions but I am run out of hope to maintenance my laptop
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Last edited by osama31; 04-09-2014 at 04:42 AM..
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Old 08-13-2014, 04:20 AM   #51
commandlinegamer
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Default Re: Sony Vaio VPC-SB26FG cannot power on

I've had a VPCCSA with that model motherboard recently, not powering on.

Replaced the cluster of three caps marked in the picture and got it starting up again.
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Old 08-22-2014, 07:29 AM   #52
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by michaeleangelo View Post
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.
Same problem thx for sharing, laptop works again.
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Old 09-05-2014, 02:39 PM   #53
Hellbringer
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Thanks for all the people that has posted solutions and things to try. I have tried some of them and i have a different problem then most so i want to get your input

I have posted a picture

The Red Square (where everyone else is having issues) seems to be good with a 0.86 reading.

The Green Square i get a .006 reading and the purple square i get 0.001 0.000.

Now i tried what michaeleangelo posted with the power supply, one lead on ground and the other on the positive side of the cap in the green square. I set the power supply to 1.5 or so volts and about 2.0 - 2.2 A and the only thing that warmed up was the south-bridge (Not hot but warm)

Now, the south bridge is right on the other side of the purple set of boxes where i am getting 0.000.

Is this a bad south bridge??? any other suggestions on things to try??

Thanks
Michael
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Old 10-25-2014, 11:32 AM   #54
Sukhvinder
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Hi, my vpc-sb does not charge battery , i checked the cnx-458 daughter board and found that IC w_pu1 is rusted and the resistance around it are also rusted. could anyone help and let me know the values of the following resistances
w_pr31, w_pr46, w_pr47, w_pr17.
Thanks
Sukhvinder
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Old 10-26-2014, 05:47 AM   #55
datom
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Default Re: Sony Vaio VPC-SB26FG cannot power on

w_pu1= 74HCT253D

w_pr31= 100K
w_pr46= 100K
w_pr47= 100K
w_pr17= 300K
Size 0402

Last edited by datom; 10-26-2014 at 05:50 AM..
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Old 03-12-2015, 09:28 AM   #56
ranjit8083
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Hi, I have 2 or 3 of the VPCSB laptops with these MBX-237 Motherboards, 2 x i5's and 1 x i7. Does anyone in UK offer a repair service on this board, i'd like to get them repaired if possible. I have no experience of soldering. I normally just swap out laptop components to get laptops working again so left with these faulty ones. Preferably want to get the i7 repaired.

Thanks
Ranjit
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Old 03-20-2015, 01:58 AM   #57
mangtomas
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Default Re: Sony Vaio VPC-SB26FG cannot power on

ive have the same problem my DCBATOUT as labeled in the schematics is shorted to ground,i cant trace the shorted one cause i have no label in main board thats what makes it difficult to trace,
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Old 03-24-2015, 03:27 PM   #58
aqibi2000
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Unhappy Re: Sony Vaio VPC-SB26FG cannot power on

Quote:
Originally Posted by mangtomas View Post
ive have the same problem my DCBATOUT as labeled in the schematics is shorted to ground,i cant trace the shorted one cause i have no label in main board thats what makes it difficult to trace,
We require the boardview for this schematic.

I have the software which I can upload here, but not the boardview file for the MBX237
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Old 03-31-2015, 02:10 AM   #59
freeman2006
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Default Re: Sony Vaio VPC-SB26FG cannot power on

Hello Everyone, I have similar problem with my Sony did not power up. The motherboard is same mbx-237. When connect the power only battery charging, when press the power button the battery led dimmed ); and nothing. Any ideas?
Thanks
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Old 04-07-2015, 09:03 PM   #60
mangtomas
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Default Re: Sony Vaio VPC-SB26FG cannot power on

cook its,its hard to troubleshoot if the mb has no label
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