HP Pavilion ZT1135 Display Problem

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My daughter's college notebook's display has died.  Originally, it was
intermittent, but now it's died completely.  I know the age (Purchase
Date: July 2002) eliminates any major work from a cost-effective point-
of-view, but I would like to repair it for her for use as a secondary
computer. She's now in school obtaining a second bachelor's degree.

I am an electronics tech, and built all of of home tower desktop
systems since the early 90s, and have experience working on IBM
ThinkPads, but not HP Pavilions.

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inverter module.  I found a new one dirt cheap on eBay, and bought
it.  But, the inverter appears not to the the problem.

Here are the symptoms:

1). Originally, the display would blank out, but there would be
vertical bars faintly visible on the screen.  This is with the typical
workload of a college student in mind - after a couple of hours of
work, the display would blank out with the vertical bars.

2).  The ZT1135 would work fine when connected to an external monitor
with the VGA connector on the back panel.  This would appear to
eliminate the video system per se, but not perhaps some interface
circuitry to the LCD panel.

3). After it sat in a closet for several months, I booted it and all
worked well.  I tried this several times over a week, and the LCD
panel worked flawlessly each time.  However, I was only using the
computer about half an hour each time.

4).  I decided to conduct a burn-in test, and left the computer on for
a couple of hours.  The display initially failed in the normal failure
mode with vertical bars faintly visible.  And, later, it blanked out
completely with a black screen.

5).  This has been its condition while using the ZT1135 to type this
post using an external monitor.  However, the LCD panel display just
came back on while typing symptom number 4! This is the first time the
LCD panel has worked in over a week.

6). After about 5 minutes, the LCD panel would toggle from normal
operation to now a fully white screen.  In completing this post, it
has toggled between fully working to a white screen four times.

The backlight is OK, as I confirmed this when I replaced the inverter
module initially.  When the screen had no video, the backlight could
be seen from behind the LCD panel (Since I had to dismantle the cover
to replace the inverter).

One would think that there are two possibilities now: 1). the LCD
panel, and 2). the cable from the motherboard to the inverter and the
panel. Note:  With the sudden re-emergence of the LCD panel's display
while typing this post, the cable was never moved or flexed.  It's
almost looking like the panel may be the culprit - perhaps

Any thoughts on this?  Obviously, I don't want to spend very much
money on this, but otherwise the ZT1135 is in perfect condition.


Re: HP Pavilion ZT1135 Display Problem

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You define problem is correct, but LCD's problem is no way you can
fix. I recommended you to send your laptop to Professional repair at:
www.laptopsprofessional.com. They have discount for student. they're
reliable, quality work, fast service and low price guaranteed. NO fix-
No charge.

Re: HP Pavilion ZT1135 Display Problem

Since you have verified that the video card works properly, and you have
already replaced the invertor, the next step is to replace the LCD

The cheapest option will be to find a broken unit on ebay that has a
working LCD screen, or see if you can obtain a working lcd from a reputable
vendor on ebay.


The listed URL links to an ebay search that has some lcd screens for the
ZT1135 units.  The other option, is to search by the LCD panel model number
for the specific part, and obtain it that way.  Chances are likely that it
may have been used by more than one OEM for laptops across different
computer makers.

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Ds.Laptop.Repair at gmail dot com

Re: HP Pavilion ZT1135 Display Problem

Thanks to those who replied.  I suspected it was the LCD panel, but
was not ready to take the leap on this without consulting those who
may have experience with this on a day-to-day repair basis.  My area
of concentration is RF circuits, and not laptop repair.  Given the
generally low price of brand-new laptops today, one can't justify
putting too much into the repair of an "older" 1.2GHz Celeron-based

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