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VanguardLH 11-20-2011 10:55 PM

Re: any way to get power to a computer with broken connector
bpuharic wrote:

> i appreciate the answers about the broken power connector on my
> computer, so let me ask a different question
> is there a way to get 110V power to a computer if the connector is
> broken? ideas? thanks everyone

The problem is that the battery could be used as a smoothing capacitor
in the charging/power circuit. If you have a dead battery (unchargeable
or shorted) or you remove it with the expectation that you will use only
AC power for the laptop, the laptop won't power up. With an unusable or
missing battery, the laptop won't turn on because it's missing the
battery for use as a capacitor. You can't simply replace the battery
with a huge capacitor because the battery also acts as regulator in that
it will only provide as much voltage as the number of cells contained
within the battery pack. The battery eliminator you want would either
have to incorporate its own battery for capacitance and regulation or
provide a large capacitor (probably more expensive than the battery)
along with its own voltage regulation. Yes, there are voltage
regulators you can buy where you can dial/select their output voltage
(dial in the VA rating of the wall adapter divided by the nominal
terminal voltage of the battery) and mad battery amperage to match the
battery. Connecting this in place of the battery, the device should
think it's operating from a battery. Sorry, I know of voltage
regulators (bought as testing gear) and don't know if someone has made a
"battery eliminator" (
for laptops. I suspect most would expect to plug into the power
connector (yours is damaged) rather than contrive a myriad of bogus
battery shells to slide into the battery bay to make contact with the
battery contacts inside. There is a lot of variation in battery packs
amongst the different laptop makers and their models.

Since you're not taking this to a computer shop to have them open the
case and look inside to see what damage was actually done, you'll be
taking the case apart yourself, especially if you're thinking of
committing some frankenjob on your laptop. Then you can tell what
damage was actually performed.

Just remember that you'll have to provide some type of strain relief on
the power cord if you permanently attach it to something inside the
case. The connector provided a break-away connection if the power cord
got yanked. Now you'll have to think about how to rigidly attach the
cord to the case to prevent later damage even if just by trying to move
your laptop and you yank on the power cord.

Hard to tell what type of frankenjob you will need inside the case until
you actually look inside to see what got damaged. Yes, you could snip
off the connector on the end of the power cord and solder it to the
contacts to which the case connector went provided that's all that is
unbroken. In the case Paul noted about a separate PCB used just for the
power connection, it looks like there was still a coil there to
eliminate noise so you'll still want to include that in the circuit.

Rather than find an expensive and likely unportable voltage regulator
setup or clumsy battery eliminator (which may not work without a working
power connector on the laptop unless you solder the regulator's output
to the battery contacts inside the laptop), I'd look inside to see what
repairs you could do.

VanguardLH 11-22-2011 06:08 AM

Re: any way to get power to a computer with broken connector
bpuharic wrote:

> good analysis..was thinking of a large knot in the cord inside the
> case, perhaps epoxied to the inside of the case...

That's the cheapie way. You have to make sure you tie the knot as tight
as possible since tightening will happen when you accidentally yank the
power cord. The hole has to be just barely larger than the cord and I
suspect the hole where you remove the 2-pole slide connector is too
large. You could use something like:

Also to remember is that you want to restrict how far the cord will bend
since, after all, wires break with repeated bending under a small
diameter. It's how you break metal by flexing back and forth by going
to an acute angle on each bend. While it is a stranded cord, each
strand is a solid wire and will break with repeated over bending. The
more strands that break the higher resistance the cord due to the less
effective diameter of the remaining strands. So you might think about a
strain relief that increases resiliency at the cord exit point in the
case, something like:

You've seen those used many times (but might only have seen the external
tail portion). Alas, those are usually molded onto the end of the cord;
i.e., the strain relief is part of the cord assembly. They usually also
require a square cutout with a ridge along the edge to hold the strain
relief to the case. You can get some that are separate, you run the
cord through them, and then crank down on a bushing to secure it to the
cord, like:

These have the advantage that they can be used with your old power cord
(you'll have to get the correct inside diameter to match to your cord's
size) and use a round hole in the case that you can drill out (and may
even be able to use with or enlarge the old power connector hole).

VanguardLH 11-23-2011 04:16 AM

Re: any way to get power to a computer with broken connector
Oops, didn't paste in the link to show one type of cord retainer.

> You could use something like:

You'll see a recess around the retainer. That's the size of the hole in
the case. The outdent is a bit bigger so you have to squeeze the
retainer to get it into the hole. Basically you wrap it around the cord
(usually a flat or 2-wire version) and is ess'es into the retainer as
you squeeze the retainer. You squeeze a bit more to force the retainer
with cord inside into the hole. Although the retainer expands a bit
after getting into the hole, it's slight and the cord is still held by
the retainer.

The cheapest way is to just use a rubber grommet. All this does is
protect the insulation of the cord from chaffing against the case to
eventually wear through the insulation. It's not a strain relief but if
you're thinking of just tying a knot in the cord on the inside of the
case or using a cable tie to make the "cord+tie" bigger than the hole
then you should still consider protecting the cord against damage from
wearing out its insulation when rubbing against the case.

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