On 02/07/2012 14:39, Jim K wrote:
On Jul 2, 1:40 pm, Jim wrote:
On Jul 2, 12:53 pm, "Man at wrote:



On Jul 2, 12:39 pm, Jim wrote:

do laptop chargers "sense" and adjust their output somehow?? meaning I
can't actually say 100% it's the charger that's shagged& just acquire
a new one...?

All help appreciated

Cheers
Jim K

All the "chargers" I've seen are just switch mode power supplies.
Indeed, the generic replacements (rather than branded) ones make very
good power supplies for other uses. Shouldn't cost mor ethan £20 for a
new one.

The charging intelligence is in the laptop and/or battery.

MBQ

Righto.

So I chopped the jack of the end to reveal a 3 core cable (which
surprised me a bit - was expecting 2)

There's an outer screen of decent multistrand (1) , then inside that
another smaller screen (2)& a core (3)

Now I can indeed get 19.5 from the bare end from the tranny -across 1
& 2
When I test across from 3 to 2 - i get 12.5v...

On the jack plug end (now removed and opened up to check) there are
indeed 3 connections - Outer screen (1) to outside of jackplug, inner
screen (2) to (appears to be) the inner surface of the jackplug ??,&
Central core (3) to centre pin.

Is this making any sense to anyone?

Cheers
Jim K

now bodged back together - but I reckon it's still same as b4.

Haven't got the lappy here so can't check...

If it's a Dell, the third core is used by the laptop to check for a
genuine Dell power supply, and if it isn't there or has the wrong
voltage on it, the battery won't charge. You get the same symptoms if
the third core is broken or the connector on the PCB is dodgy, say, due
to a dodgy joint.

It's their way of locking you in to buying genuine parts only. :-/


--
Tciao for Now!

John.