Re: Laptop screen - strange problem


"G.G.Willikers" <noone@xxxxxxxxxx> wrote in message
news:94ERj.228$J16.209@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
M.I.5¾ wrote:
"abd08" <dejaonly@xxxxxxxxxxx> wrote in message
news:80b906ba-2ec5-435d-ab64-0f7c00ba8adf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi All,

Have a panasonic CF-W2 laptop, and the following has happened:

1. From about 2 months ago, very randomly, the screen would
"glitch" (jump as if the VSYNC was off, NOT go off/out). This would
occur several times a day, or sometimes not at all. It would also
occur regardless of condition - just sitting on the desk, perfectly
stable, and then "glitch". Tilting the screen had no effect either in
making it glitch, making glitching worse, or stopping it glitching.

2. This morning everything was as per 1. However, got home and started
using it: At first, everything was normal. Walk away for 20mins and
come back, and there is a pitch black patch (about 3cm by 2cm) in the
bottom left corner. Upon touching it, it was extremely hot. After
lowering the brightness on the LCD, for the first minute I got
continuous glitching (for the first time ever), then the glitching
slowed down/gone back to normal, and now the spot has gone away. The
screen is much cooler, but very dim now! =)


1. may be unconnected, but the black patch that was very hot is due to a
problem with the Cold Cathode tube that illuminates the display (or can
be the tube's associated inverter - but my money is on the tube itself).
These tubes seem to be somewhat misnamed because the cathodes aren't cold
at all, they actually get very hot in use (the term 'cold cathode' has a
very different meaning). There is a failure mode of these tubes that
causes the cathode at one end to get even hotter than it really ought to.
This heats up the Liquid Crystal display immediately adjacent to it which
ceases to work as it should and exhibits a black patch. The display
often recovers as it cools down, but continued operation in this manner
will result in its eventual destruction. Replacing tubes is not for the
faint hearted.

you aint just whistling dixie there pal.
I finally attempted this recently with success, but it tested every ounce
of patience that I had.

Replace bulb = $9.00 vs. replace 17" XWGA LCD = $199.00


I replaced one on a little 3" Casio television once. It took me around 3
hours and even then I ended up with a scratch on the inside surface of the
glass. The replacement went the same way very quickly. I hadn't realised
that although the thing ran off 8 alkaline 1.5 volt batteries, that it
should not have been run from a 12 volt AC adaptor. It took so much current
from the batteries that, with the voltage drop, it was actually a 9 volt
device needing a 9 volt adaptor.


.

Relevant Pages

  • Re: Laptop screen - strange problem
    ... making it glitch, making glitching worse, or stopping it glitching. ... problem with the Cold Cathode tube that illuminates the display (or can be ... There is a failure mode of these tubes that causes the ... Replacing tubes is not for the faint hearted. ...
    (comp.sys.laptops)
  • Re: Laptop screen - strange problem
    ... making it glitch, making glitching worse, or stopping it glitching. ... These tubes seem to be somewhat misnamed because the cathodes aren't cold at all, they actually get very hot in use (the term 'cold cathode' has a very different meaning). ... This heats up the Liquid Crystal display immediately adjacent to it which ceases to work as it should and exhibits a black patch. ...
    (comp.sys.laptops)
  • Re: Laptop screen - strange problem
    ... making it glitch, making glitching worse, or stopping it glitching. ... problem with the Cold Cathode tube that illuminates the display (or can be ... There is a failure mode of these tubes that causes the ...
    (comp.sys.laptops)