In comp.sys.ibm.pc.hardware.misc news.rcn.com news.rnc.com wrote:

"Arno Wagner" wrote in message
...
In comp.sys.ibm.pc.hardware.misc news.rcn.com news.rnc.com wrote:
Does anyone know how to replace a power supply in an HP Pavilion ZT3380
laptop please?

The power plug seems to be exceptionally loose and if the computer shuts
down, you can occasionally get it turned on again by turning the plug
around
in the socket 180 degrees so that something makes contact with something
again. But I don't think this is the whole story.

The computer does work as a desktop but once it did shut down overnight
for
no apparent reason and once during use while I was trying to soak-test it
for this very problem. When it shut down overnight, by the morning,
when I
turned it on, the orange charge light having presumably been on all
night,
it showed 0% charge. Suspicious.

More importantly it shuts down completely if you accidentally jiggle the
plug, not going to battery power at all. In addition, when you start it
with
a largely dead battery and then try to plug it in to charge the battery,
the
battery doesn't charge at all. It CAN also show an orange charge light
overnight when off and by the morning, show no increase in charge: This
doesn't just seem to be a loose plug!

I upgraded the BIOS and this seemed to improve things for a very short
while, with the new BIOS having a battery calibration utility which
worked
once. However, now it wont even charge the System Battery except
excruciatingly slowly. Isn't the system battery something like a
rechargeable CR2025? Which should discharge/charge in a few minutes.
When
the battery utility did discharge/recharge the main battery, it did do it
in
around a half an hour.

A CR2025 explodes if you charge it.
Yes, I suspected that: So the problem may well be with the CMOS battery
itself? The utility at first stopped the charging process at 99%.
Thereafter, it wont get much past about 8-10%. I wonder if this could
account for the whole problem? (see below)

Actually when I now go into the BIOS utility, I am not offered the option of
calibrating the Main Battery any more (I did go through the process of
recalibrating the main battery, - successfully, - once), just the "system"
one

We HAVE tried changing the AC adapter in case the problem was with the
internal wiring of the plug itself and isolated that as not being the
issue.

Someone once referred me to a service manual for my Pavilion 5415 which
had
a similar problem but I cant now find the reference to it (and replacing
the
power supply for the 5415 involved a completely uneconomical taking apart
of
the whole computer down virtually to the last screw!). These internal
power
supplies do occasionally come up on ebay and sell for a few bucks.
possibly
for this reason?

Hopefully the situation wont be the same for the 3880? Though an
alarming
number of them seem to come up very cheaply at places like Fry's, -
reconditioned .

(Incidentally it refers to itself on its screen panel as a ZT3000, on its
underside as a ZT3300 and on it serial number plate as a ZT3380US)

It may just be a contacrt problem. These are best tackled with contact
spary and bending the contact so that is presses firmer on the plug.
The reason why I included such an amount of detail in what could be a
contact problem is because MOST OF these symptoms don't seem to point to a
contact problem. Such as: Why can't it switch from ac to (a fully charged)
main battery like all other computers when you simply take out the plug? Why
does it shut down completely when you arent actually doing anything on the
computer if it is a contact problem? Unless the contacts inside the socket
are completely burned out, carbonised and pitted, why doesnt it charge the
battery on re-plug in if it is just a contact problem?

If it IS just a contact problem, surely just spraying it with WD40 will make
the problem completely go away for at least a while until the metal under
the 'oil' starts encountering the carbon again? And for fear of repeating
myself, why am I getting all these mysterious problems with the calibration
utility if the problem is with the contacts?

Hmm. Agreed. Sounds more like an issue with the entire power unit
in the laptop. Maybe a swithcing transistor that has a problem or
the like. Very hard to diagnise without shematics and the right
equipment.

Arno