old laptop becomes music controller

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so my wife's laptop (dell inspiron) ate it.  specifically the
motherboard ate it.  specifically the power controlling part of the
motherboard ate it such that:  with a battery, the computer runs no
problem, but it can not charge the battery with the power cord, nor can
it run off the power cord itself.  now i know that i can buy a new
motherboard, but...

the battery supplies 14.8 VDC, would fixing this be as easy as
buying/building a 14.8 VDC power supply and hooking the leads up to the
battery connection points?  The battery btw is a 6t473 standard Dell
battery for Inspirons and I am sure other types.

I would like to have it powered up all the time (with power supply that
I jury rig) and then hook it to my wireless network so I can play
music/share files.

Any suggestions on step 1, powering my deadish laptop?

Thanks in advance, please send email responses to jacob.scott@case.edu,
or, preferably, post them here.


Re: old laptop becomes music controller

On 18 Jan 2006 15:00:44 -0800, jacob.g.scott@gmail.com

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Depending what exactly what's wrong, it might not be an
expensive repair at an electronics repair shop, opposed to a
computer "swap-in-new-replacement-part" shop.

If you know someone who has dabbled in electronics, at the
board level, they might be able to fix it too.  Having
isolated the problem you are 1/2 way done.

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Maybe (probably) but ultimately depends on whether there is
any other communication between laptop and the battery
charger board (in the battery pack) and whether when it
doesn't comm, if this is considered a fault condition that
would shut off the notebook.  What you might do is put
pieces of scotch tape over all contacts but those suppling
the positive and negative14.8V and see if the laptop runs
from the battery.  If it does, that in itself is a sign it
would work to do as you described, presuming your 14.8V
supply had enough amperage which is a variable I don't know,
would shoot for 5A or so depending on what was easily
available since aftermarket, non-laptop power supplies on
the surplus market can be a lot cheaper but a
take-what-you-can-find, market.

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The biggest issue might be ensuring a reliable connection.
It would seem easiest to use an old battery pack as the
shell and contacts, unless you were to take apart the laptop
and add jumper wires to an alternate connector... which is
what I'd probably do but then again I'd probably investigate
the original supply circuit too.

Re: old laptop becomes music controller

jacob.g.scott@gmail.com wrote:
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If you can find someone who does actual repair, vs replacement, it might
not be all that difficult to fix.

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That's a lithium ion battery pack and lithium ion batteries are not
something you jut slap a voltage on to recharge. They need monitoring and,
by comparison to lead acid, a relatively sophisticated charger. That
particular battery pack also contains a battery meter and, likely, current
limiting as well as a temp monitor for the charger.

They're not terribly difficult to design with because there's a raft full
of ICs made specifically for them but just slapping a power supply across
one can cause all kinds of problems, not the least of which being it might

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If you wanted to do some kind of make shift power supply the best approach,
IMO, would be to forget the battery entirely and make an external DC supply
  that could be tacked onto the power section after the battery, a sort of
'battery eliminator'. Might have some power monitoring problems with the
then missing battery not providing any battery meter indication.

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Re: old laptop becomes music controller

thanks for the replies...

i certainly don't want to try to make a make shift battery charger,
instead i would definitely be going with the make shift power supply to
the computer itself, through the battery connections.  i hadn't thought
about the problem of the batteries communication with the computer, and
think that this may pose the problems that you have mentioned.

i feel like the issue with the laptop couldn't be that difficult, it
seems like it would be a fuse or something, or just a single wire
blown, or at least just a single component.

maybe it would be worthwhile to try to buy another broken laptop of
this kind to see what's what.  maybe i'll take it apart tonight and see
what i can see :)

thanks again, keep the ideas coming!

Re: old laptop becomes music controller

jacob.g.scott@gmail.com wrote:

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Are you sure the adapter is delivering juice ? Is the adapter
AC output, unregulated DC, or regulated DC. Using a multimeter,
you can use the AC or DC voltage range, to get some idea if
there is still output. It could be that the fuse you are
referring to, is inside the adapter. Or it could be in
the laptop itself.

Ideally, testing the adapter should be done with a small
test load on it. Comparing the voltage measured with no
load, to the voltage with a light load (like enough light
bulbs to match the adapter rated output voltage), will
tell you whether what you are seeing is real power output,
or just a bit of leakage coming through a damaged component.
It is normal for the voltage to drop wnen a load is connected
to the adapter (except in the case of a regulated DC adapter,
where the output voltage is virtually constant over the
load range - the other two types of adapters can drop their
output voltage as a function of loading).

If it isn't the adapter, then you'll need to disassemble the
laptop. If it is already considered a writeoff, I guess
taking it apart won't be much of a risk. Specifically, you'll
be looking around the power connector, where it enters the
laptop. There could be some diode and power conditioning
circuits, and you'd be looking for a fuse, or signs of
physical damage (like broken conductor, something burnt
and so on). The lithium battery should be removed and
well clear of your work area, as that is likely the most
dangerous part of the device. As with any batteries,
shorting the battery can have disasterous consequences.

At least you'll get your money's worth, in terms of a
learning experience.

Considering the price of a laptop, and your level of
experience with electronics, would it be worthwhile
to have a repair shop look at it ?


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