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Dead Sony Vaio PCG-631M laptop - power block problem.Help!

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  • Homebuilt
  • Laptops
  • Sony Vaio
  • Power
  • Systems
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November 21, 2004 10:06:19 PM

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Greetings.
I have Vaio laptop. After checking the power block it's appeared that
power voltage comes into the board and there's also first conversion of
voltage from 16V to 5.99V. No other values on parts. It's too
complicated and small to analyze PCB so I'd like to ask for any
solutions to repair it. Does anyone have a source to some diagnostic
manuals or have any idea what can I do. Thanks for answers like "throw
it away". I'd like to try to fix it.
Also I'd like to ask for a tip how to "decode" part values of SMD
elements as they're coded.
Thanks in advice.
BartMan

More about : dead sony vaio pcg 631m laptop power block problem

Anonymous
a b B Homebuilt system
a b D Laptop
November 23, 2004 5:04:29 AM

Archived from groups: alt.comp.hardware.homebuilt (More info?)

BartMan wrote:

> Greetings.
> I have Vaio laptop. After checking the power block it's appeared that
> power voltage comes into the board and there's also first conversion of
> voltage from 16V to 5.99V. No other values on parts. It's too
> complicated and small to analyze PCB so I'd like to ask for any
> solutions to repair it. Does anyone have a source to some diagnostic
> manuals or have any idea what can I do. Thanks for answers like "throw
> it away". I'd like to try to fix it.
> Also I'd like to ask for a tip how to "decode" part values of SMD
> elements as they're coded.
> Thanks in advice.
> BartMan

I am a little bit unclear because from the title of your post it seems that
you may think that the power brick is the problem here.
If it is rated at 16v output and that is what you are getting then the brick
is fine and you have a fault with the system board on your laptop.

I am not completely familiar with that particular model. However here are
some things you can try before resorting to a system board replacement (in
the UK I use clonesUK to try and obtain refurb boards, but even refurb is
not cheap) Or look on ebay for a carcass of the same model with missing
bits or a broken screen.

Find out how to do a full factory reset of the laptop (cmos the lot) I've
seen more "dead" laptops fixed this way than any other. Google should help
here.

Some Sony's won't power up without a battery in place (although from memory
you at least get a flash from the status lights) Check the battery is
operational and inserted correctly.

Does the battery charge circuit work (can you get the battery to charge, do
the charge status LED's do anything, charge voltage measured at battery
contacts etc etc)

The 6v you are measuring will be only one of the several voltages derived
from the 16v input, check the other side of the PCB. Actually 6V sounds a
little unusual to me, you usually expect to see PC like voltages around the
guts of a laptop +3.3 +5 +12 and so on.

Strip everything you can from the systemboard (hard drive,Optical Drive,
Screen,Pointing device,BL circuit, miniPCI cards etc etc) does it power up
then ?

If you can get a charge into the pack, try this to see if the laptop will
start (don't attempt to charge pack from a bench PSU unless you REALLY know
what you are doing, charged without careful current regulation and safety
measures those things become bombs) perhaps find someone with a working
similar laptop to charge the pack for you.


It's worth mentioning that almost nobody repairs these things to component
level, Even the Sony service info does not go to that detail
November 26, 2004 3:12:13 PM

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hello.

Wayne Stallwood napisał(a):

>
> I am a little bit unclear because from the title of your post it seems that
> you may think that the power brick is the problem here.
> If it is rated at 16v output and that is what you are getting then the brick
> is fine and you have a fault with the system board on your laptop.
Yes. I said it unclear. There's a problem on mainboard.

> Find out how to do a full factory reset of the laptop (cmos the lot) I've
> seen more "dead" laptops fixed this way than any other. Google should help
> here.
I'll try. I've found a reset button well hidden on mainboard with a sign
"reset". There's a little hole in the case, to put something thin and do
a reset but there's no "reset" sign on the case, so until you open the
case you don't know that is the reset button. Could that be ordinary
system reset or it's a special reset for inside curcuitry and cmos?

> Some Sony's won't power up without a battery in place (although from memory
> you at least get a flash from the status lights) Check the battery is
> operational and inserted correctly.
That can be a good hint becasue the former owner said that batter is
very weak. But I've heard that all laptops power on without battery only
connected to mains supply.

> Does the battery charge circuit work (can you get the battery to charge, do
> the charge status LED's do anything, charge voltage measured at battery
> contacts etc etc)
There's no status LED :(  There are some voltages around 5V on battery
connection pins that sticks from mainboard. I don't know if these are
correct. Battery is 13V so voltage on the pins should be around that
value to charge battery but maybe it goes up when the battery is
connected. I've checked theese voltages without battery.

> The 6v you are measuring will be only one of the several voltages derived
> from the 16v input, check the other side of the PCB. Actually 6V sounds a
Yes, that's what I expected.
> little unusual to me, you usually expect to see PC like voltages around the
> guts of a laptop +3.3 +5 +12 and so on.
I agree.

> Strip everything you can from the systemboard (hard drive,Optical Drive,
> Screen,Pointing device,BL circuit, miniPCI cards etc etc) does it power up
> then ?
I did it. Nothing happened. There were no voltage on power-on button. I
suppose there should be some to close the circuit to make some chip turn
power on.

> If you can get a charge into the pack, try this to see if the laptop will
> start (don't attempt to charge pack from a bench PSU unless you REALLY know
> what you are doing, charged without careful current regulation and safety
> measures those things become bombs) perhaps find someone with a working
> similar laptop to charge the pack for you.
It's veryyyy hard. I'll try. I'll see if there are another vaio models
that can run with my battery.

> It's worth mentioning that almost nobody repairs these things to component
> level, Even the Sony service info does not go to that detail
I know that. They replace whole mainboards...

But I have no choice if I want to have own laptop.

Thank You for response. I'm waiting for another posts.
Greetings.
BartMan
Anonymous
a b B Homebuilt system
a b D Laptop
November 29, 2004 3:09:50 AM

Archived from groups: alt.comp.hardware.homebuilt (More info?)

BartMan wrote:


> I'll try. I've found a reset button well hidden on mainboard with a sign
> "reset". There's a little hole in the case, to put something thin and do
> a reset but there's no "reset" sign on the case, so until you open the
> case you don't know that is the reset button. Could that be ordinary
> system reset or it's a special reset for inside curcuitry and cmos?

Either way it is worth a shot, it may well be a cmos reset but that will do
you no harm, Laptops don't usually have many "in depth" settings in the
cmos so you aren't going to loose anything important.


> That can be a good hint becasue the former owner said that batter is
> very weak. But I've heard that all laptops power on without battery only
> connected to mains supply.

Measure the battery voltage (there may be quite a few pins on the battery)
but usually on Viao's the first and last pin should give you the battery
voltage. It should be at least 40-50% of full rated voltage. Charge voltage
should be 10-20% higher than battery nominal voltage but as you say unless
the charge circuit detects the battery is present it may not run.

> There's no status LED :(  There are some voltages around 5V on battery
> connection pins that sticks from mainboard. I don't know if these are
> correct. Battery is 13V so voltage on the pins should be around that
> value to charge battery but maybe it goes up when the battery is
> connected. I've checked theese voltages without battery.
>

Yes that is possible.

>> The 6v you are measuring will be only one of the several voltages derived
>> from the 16v input, check the other side of the PCB. Actually 6V sounds a
> Yes, that's what I expected.
>> little unusual to me, you usually expect to see PC like voltages around
>> the guts of a laptop +3.3 +5 +12 and so on.
> I agree.
>
>> Strip everything you can from the systemboard (hard drive,Optical Drive,
>> Screen,Pointing device,BL circuit, miniPCI cards etc etc) does it power
>> up then ?
> I did it. Nothing happened. There were no voltage on power-on button. I
> suppose there should be some to close the circuit to make some chip turn
> power on.

Usually the power buttion works by grounding a line (usually 3.3 or 5v) that
is supplied via a current limiting resistor. When the switch is closed the
line is dropped to 0v (because the other side of the switch is ground) an
IC or transistor somewhere sees that and fires the thing up. If you are
measuring nothing each side of the switch then that could be a problem.

Given the odd voltages you are seeing at the battery and the strange 6v near
the input. I am wondering if your ground reference is at the wrong point.
Some stuff has a floating ground (so that they can easily get + and -
supply rails) where are you putting the minus lead of your meter for these
measurements ?
>

Most laptops feed the supply from the power brick into a switching regulator
(sort of half a switch mode power supply) this in turn supplies voltages
that are needed internally. They use switching regulators because they are
more efficient than conventional regulator (like LM7805's) The switching
regulator circuit will consist of the switching regulator itself a small
inductor and perhaps a couple of mosfets. The battery will feed into the
input of the switching circuit (it needs to because the battery voltage
changes with load and charge level) At a point before the switching
regulator there will be a simple voltage drop circuit that supplies power
to start the regulator and supply other circuits that need to run before
power on (like the power button, wake up on lan that sort of thing)

One thing worth looking at is the current drawn from the PSU when the laptop
is in it's current state. This is a bit tricky as you need to break the +16
volt connection and put a current meter in circuit. If you are comfortable
working with mains powered equipment sometimes the easy way to do this is
to dismantle the power brick and unsolder the +v output. but take care in
prodding around the live (or recently unplugged) exposed power pack.
!