I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly if the
power is removed. There are only ever two lights on on the front of the
laptop, one for the mains supply and one for the hard drive. The battery
light never comes on. The power meter in Windows does identify the battery
and shows it as having zero charge.

I've tried battery recalibration and a new battery has also been tried but
neither helps, it still refuses to charge. More in hope than in expectation
I've opened it up to have a look around but there's nothing obvious to see.

I'm guessing something has gone wrong with the internal charging circuitry.

Is there anything else I can do or have I come to the end of repair options
(short of motherboard replacement)?

Tim

Tim Downie wrote:
I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly if
the power is removed. There are only ever two lights on on the front of
the laptop, one for the mains supply and one for the hard drive. The
battery light never comes on. The power meter in Windows does identify
the battery and shows it as having zero charge.

I've tried battery recalibration and a new battery has also been tried
but neither helps, it still refuses to charge. More in hope than in
expectation I've opened it up to have a look around but there's nothing
obvious to see.

I'm guessing something has gone wrong with the internal charging circuitry.

Is there anything else I can do or have I come to the end of repair
options (short of motherboard replacement)?

Tim

Remove the battery and see if you can measure the voltage present at
the terminals the battery connects to while the charger PS is plugged
in. If you see no voltage there, it is a safe bet that the internal
components of the charging circuit are at fault. If there is voltage
there, you might consider the possibility of the terminals not making
proper contact with the battery.

Ken wrote:
Tim Downie wrote:
I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly
if the power is removed. There are only ever two lights on on the
front of the laptop, one for the mains supply and one for the hard
drive. The battery light never comes on. The power meter in Windows
does identify the battery and shows it as having zero charge.

I've tried battery recalibration and a new battery has also been
tried but neither helps, it still refuses to charge. More in hope than in
expectation I've opened it up to have a look around but there's
nothing obvious to see.

I'm guessing something has gone wrong with the internal charging
circuitry. Is there anything else I can do or have I come to the end of
repair
options (short of motherboard replacement)?

Tim

Remove the battery and see if you can measure the voltage present at
the terminals the battery connects to while the charger PS is plugged
in. If you see no voltage there, it is a safe bet that the internal
components of the charging circuit are at fault. If there is voltage
there, you might consider the possibility of the terminals not making
proper contact with the battery.

The contacts all look undamaged and are soldered securely to the
motherboard. I'm not sure which contacts do the charging and what voltages
to expect so I've not done that (yet).

Tim

On Nov 18, 5:47*am, "Tim Downie" wrote:
I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly if the
power is removed.

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

Basically, look at the power handling discrete components (fuse, sense
resistor, PMOS switch transistors, etc.) near the battery connector.

"whit3rd" wrote in message ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).


This is where I have to admit to a considerable amount of ignorance. What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. Using my wife's Vista disabled laptop).

Tim Downie wrote:

wrote in message ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).


This is where I have to admit to a considerable amount of ignorance. What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. Using my wife's Vista disabled laptop).



No insult intended, but it sounds like this task might be beyond your
abilities. First most laptops are not easy to disassemble. You could
very well do more damage than good. If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.

On Nov 18, 9:06*pm, Ken wrote:
Tim Downie wrote:

*wrote in ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). *It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

This is where I have to admit to a considerable amount of ignorance. *What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. *Using my wife's Vista disabled laptop).

* * * * No insult intended, but it sounds like this task might be beyond your
abilities. *First most laptops are not easy to disassemble. *You could
very well do more damage than good. *If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.


It does sound like an electronic fault with the charging circutry if
youve tried a new battery. And you're way short of the skills to
diagnose and fix that.

Mains only laptops are pretty useful. If you had more skills I'd
mention adding a basic slow charger circuit, bypassing the dead fast
charger.


NT

"Ken" wrote in message ...
Tim Downie wrote:

wrote in message ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).


This is where I have to admit to a considerable amount of ignorance. What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. Using my wife's Vista disabled laptop).



No insult intended, but it sounds like this task might be beyond your
abilities. First most laptops are not easy to disassemble.

I've taken a few apart. What's more, I've put most of them back together again. ;-)

You could
very well do more damage than good. If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.

It's several years old and an "extra" laptop in the household. I doubt it would be economically worth trying to get repaired unless the cost is low enough.

I won't deny that it's probably beyond my skills. I was just hoping there might be something obvious that was within my ability.

Tim

On Nov 18, 10:54*pm, "Tim Downie" wrote:
"Ken" wrote in ...
Tim Downie wrote:

*wrote in ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). *It sounds like the charging circuitry isn't doing its job..
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

This is where I have to admit to a considerable amount of ignorance. *What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. *Using my wife's Vista disabled laptop).

No insult intended, but it sounds like this task might be beyond your
abilities. *First most laptops are not easy to disassemble.

I've taken a few apart. *What's more, I've put most of them back together again. ;-)

*You could
very well do more damage than good. *If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.

It's several years old and an "extra" laptop in the household. *I doubt it would be economically worth trying to get repaired unless the cost is low enough.

it wont be remotely worth it

I won't deny that it's probably beyond my skills. I was just hoping there might be something obvious that was within my ability.

Tim

regrettably not


NT

On Nov 19, 12:18*am, Tabby wrote:
On Nov 18, 10:54*pm, "Tim Downie" wrote:





"Ken" wrote in ...
Tim Downie wrote:

*wrote in ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). *It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

This is where I have to admit to a considerable amount of ignorance. *What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. *Using my wife's Vista disabled laptop).

No insult intended, but it sounds like this task might be beyond your
abilities. *First most laptops are not easy to disassemble.

I've taken a few apart. *What's more, I've put most of them back together again. ;-)

*You could
very well do more damage than good. *If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.

It's several years old and an "extra" laptop in the household. *I doubt it would be economically worth trying to get repaired unless the cost is low enough.

it wont be remotely worth it

I won't deny that it's probably beyond my skills. I was just hoping there might be something obvious that was within my ability.

Tim

regrettably not

NT- Hide quoted text -

- Show quoted text -

The simplest and cheapest workaround for such problems is to buy on
eBay a "spares or repairs" machine that uses the same battery and hope
the charger circuitry still works. More elegantly, you can get
standalone chargers for some batteries, but the cost will be about the
same.

Chris

On Nov 19, 12:30*am, wrote:
On Nov 19, 12:18*am, Tabby wrote:



On Nov 18, 10:54*pm, "Tim Downie" wrote:

"Ken" wrote in ...
Tim Downie wrote:

*wrote in ...

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). *It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

This is where I have to admit to a considerable amount of ignorance. *What would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. *Using my wife's Vista disabled laptop).

No insult intended, but it sounds like this task might be beyond your
abilities. *First most laptops are not easy to disassemble.

I've taken a few apart. *What's more, I've put most of them back together again. ;-)

*You could
very well do more damage than good. *If this computer is worth anything,
you might try to find someone who has some skill repairing electronic items.

It's several years old and an "extra" laptop in the household. *I doubt it would be economically worth trying to get repaired unless the cost is low enough.

it wont be remotely worth it

I won't deny that it's probably beyond my skills. I was just hoping there might be something obvious that was within my ability.

Tim

regrettably not

NT- Hide quoted text -

- Show quoted text -

The simplest and cheapest workaround for such problems is to buy on
eBay a "spares or repairs" machine that uses the same battery and hope
the charger circuitry still works. More elegantly, you can get
standalone chargers for some batteries, but the cost will be about the
same.

Chris

I reckon a resistor from power pack out to battery + fitted inside the
lappie would be simpler & cheaper. Charging would be very slow, but
quite workable if its not used a lot on battery.


NT

"Tabby" wrote in message
...

The simplest and cheapest workaround for such problems is to buy on
eBay a "spares or repairs" machine that uses the same battery and hope
the charger circuitry still works. More elegantly, you can get
standalone chargers for some batteries, but the cost will be about the
same.

Chris

I reckon a resistor from power pack out to battery + fitted inside the
lappie would be simpler & cheaper. Charging would be very slow, but
quite workable if its not used a lot on battery.

Even simpler would be to buy a rechargable battery of the same or close
voltage as the AC supply and fit it with the proper connector to plug the
battery into the AC charger slot. The battery could be recharged manually.

You can familiarize yourself with many components, parts etc, by looking at
catalogs and manufacturers' websites of same items.

Another clue to look for on circuit boards, are the component designation
legends sometimes screenprinted onto the boards before they're
stuffed/populated with te components.
Fuses, for example, are generally designated Fx (F101, F200 etc). The
components on that particular board may, or may not, be clearly marked.. but
as you take more stuff apart (and it sounds like you will be), you'll become
more familiar with various components' appearances.
Eventually, you'll be able to spot items as scarce as SMT fuses very
quickly, at a glance.

That's how it gets started. Before ya know it, you'll have piles of stuff
sitting around to tear apart. It's not like there is likely to be a shortage
of inoperative electronic gear, any time soon.

Alternatively, research websites for similar problems with the same
brand/model of laptop. Having a little too much knowledge never hurt anyone
that I know of.

Save shortcuts to helpful websites and make some notes (paper or text files)
for future use.

Generally, open fuses aren't the only problem, but with a charging circuit,
it's possible that a weak or defective/worn out battery may have caused the
fuse to open.
Checking other components in the vicinity with an ohmeter may reveal other
stressed or faulty components.
Many modern components don't show visible signs of being defective, so a
decent DMM digital multimeter will prove to be very useful in doing quick
checks of various components.
Working on and testing low voltage circuits is generally fairly safe, but be
sure to read and understand the cautions regarding safe use of testing
equipment and use the precautionary info to develop safe work practices.

Over the years I've heard/read that there are some good DVDs covering a lot
of topics related to basic electronic circuits, so some of those may be
beneficial.

--
Cheers,
WB
..............


"Tim Downie" wrote in message
...

This is where I have to admit to a considerable amount of ignorance. What
would a surface mounted fuse look like and would it be visibly blown?

Tim
(apologies for stupid quoting. Using my wife's Vista disabled laptop).

Hi Tim,

Tim Downie wrote:
I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly if
the power is removed. There are only ever two lights on on the front of
the laptop, one for the mains supply and one for the hard drive. The
battery light never comes on. The power meter in Windows does identify
the battery and shows it as having zero charge.

I've tried battery recalibration and a new battery has also been tried

When the "new" battery was installed in the machine, did the battery
light come on? What did Windows report the battery's condition?
(was it really a *new*, CHARGED battery that you used?)

but neither helps, it still refuses to charge. More in hope than in
expectation I've opened it up to have a look around but there's nothing
obvious to see.

Bents pins (or pins that are stuck "retracted" in the battery
connector)?

I'm guessing something has gone wrong with the internal charging circuitry.

Is there anything else I can do or have I come to the end of repair
options (short of motherboard replacement)?