Can I use Laptop monitor screen with desktop?

[Ritter 197]

Is there a way to use the HP laptop screen with a HP desktop?
I want to test a monitor at a friend whose computer (also HP) seems going
off after a while, yet graphics card is fine, power source not hoy, monitor
not hot, all cables new. And he has no other monitor to test it with.

 

[Paul]

Is there a way to use the HP laptop screen with a HP desktop?
I want to test a monitor at a friend whose computer (also HP) seems
going off after a while, yet graphics card is fine, power source not
hoy, monitor not hot, all cables new. And he has no other monitor to
test it with.

A laptop screen uses a "private" rather than a "public"
interface. The laptop cable is intended to work with the
laptop main body, and the cable is likely to only work
well if the cable is kept pretty short.

To use a laptop screen, you'd have to find a part number on it,
download the datasheet, see what data format it uses, and try
and convince the driving device to put out that format. And
that isn't likely to happen.

This is an example of an LCD panel, so you can understand
that it is a "raw" device, and needs some knowledge about
electronics to use it. It looks to me like the interface
is similar to DVI (serial interface, diff pair per R,G,B plus
a clock) but it looks like vanilla LVDS serial, rather than being a
transition minimized format.

http://www.datasheetcatalog.org/datasheet/nec/NL10276BC28-05D.pdf

TMDS is what might come out of a DVI connector. There is a
10 bit value on each of the R,G,B signals. It must be
decoded to give a "raw" 8 bit value. So you need a decoding
stage. In the case of the above sample LCD panel, the panel is
a 6 bit type, so two of the bits must be throw away or
otherwise provided for (dithering? dunno how you drive a
6 bit panel). And the data is in a high speed serial format
on the panel as well. So this takes a handful of electronics,
to convert from DVI/TMDS to something that little panel can use.

http://en.wikipedia.org/wiki/TMDS

On a computer monitor, you'll find a printed circuit board
with adaptation chips, fastened to the back of a raw panel.
In the case of the laptop screen, that adaptation circuit
is missing. The GPU is convinced to put out the necessary
data pattern on say, an SDVO output interface (parallel bus?).
Maybe there is another little driver chip, such as an
LVDS transmitter (a parallel to serial converter), to
finish the job.

The GPU in the laptop, might use a concept equivalent
to the SIL164. I don't think this is still in production,
but what it does, is parallel to serial conversion, for
driving a panel. The high speed serial on this is not
transition minimized, and the output cable stays
short.

http://web.archive.org/web/20021023004158/www.siimage.com/documents/SiI-DS-0021-A.PDF

Sounds like a fun project if you can find the chips, own
a soldering iron etc etc.

If the laptop display had a "public" interface, followed
an accepted standard, then it would be more useful for
what you want to do. Such a device is also known as
a desktop LCD monitor.

Paul

 

[Patrick Keenan]

Is there a way to use the HP laptop screen with a HP desktop?
I want to test a monitor at a friend whose computer (also HP) seems going
off after a while, yet graphics card is fine, power source not hoy,
monitor not hot, all cables new. And he has no other monitor to test it
with.

There is software that will duplicate the display on other systems, but it
won't provide a representative test.

Instead, reverse the scenario and connect the monitor to your laptop. Run
it as the primary or secondary, it deoesn't matter. If the monitor is at
fault, it will fail the same way.

HTH
-pk

 

[Ritter 197]

There is software that will duplicate the display on other systems, but it
won't provide a representative test.

Instead, reverse the scenario and connect the monitor to your laptop.
Run it as the primary or secondary, it deoesn't matter. If the monitor
is at fault, it will fail the same way.

HTH
-pk

Pat, that sounds like a great idea, but I am not sure how to do that.
Presently his desktop runs to the desktop monitor (actually a digital TV,
since he can hardly see at all and needs a larger surface)
Now what would you want me ?

 

[Shenan Stanley]

Is there a way to use the HP laptop screen with a HP desktop?
I want to test a monitor at a friend whose computer (also HP) seems
going off after a while, yet graphics card is fine, power source
not hoy, monitor not hot, all cables new. And he has no other
monitor to test it with.

There is software that will duplicate the display on other systems,
but it won't provide a representative test.

Instead, reverse the scenario and connect the monitor to your
laptop. Run it as the primary or secondary, it deoesn't matter. If the
monitor is at fault, it will fail the same way.

Pat, that sounds like a great idea, but I am not sure how to do
that. Presently his desktop runs to the desktop monitor (actually a
digital TV, since he can hardly see at all and needs a larger
surface) Now what would you want me ?

Connect the monitor (digital tv) to your laptop and display your laptop
output on the external monitor (very few laptops I can think of cannot hook
to external monitors like this.) I am guessing he is connecting using VGA
or DVI - you should have at least a VGA output on your laptop - use it and
whatever keystrokes pushes the display to the external port to test the
monitor/TV to see if it is the problem or if the computer/video card is the
problem. Bring your own cables too - so you can make sure that is not the
problem.

If you verify the monitor still goes off connected to your laptop after a
short time - just like when connected to his desktop - you are done. The
monitor is bad. Repair/replace it.

I got a 28 inch widescreen computer monitor the other day for just under
$325 after shipping. Added another 2 years of warranty to it for just under
$100 more (3 years total.)

 

[Patrick Keenan]

Pat, that sounds like a great idea, but I am not sure how to do that.
Presently his desktop runs to the desktop monitor (actually a digital TV,
since he can hardly see at all and needs a larger surface)
Now what would you want me ?

There should be a VGA connector on both the TV and the laptop. You may
need to play with the laptop video settings to get this to work with a TV,
and the results often aren't very good, and it may take a reboot or two, but
you should get it to work.

The fact that the monitor is actually a TV is a rather significant piece of
information. You may need to contact the TV manufacturer's service.

HTH
-pk

 

[Patrick Keenan]

Connect the monitor (digital tv) to your laptop and display your laptop
output on the external monitor (very few laptops I can think of cannot
hook to external monitors like this.) I am guessing he is connecting
using VGA or DVI - you should have at least a VGA output on your laptop -
use it and whatever keystrokes pushes the display to the external port to
test the monitor/TV to see if it is the problem or if the computer/video
card is the problem. Bring your own cables too - so you can make sure
that is not the problem.

If you verify the monitor still goes off connected to your laptop after a
short time - just like when connected to his desktop - you are done. The
monitor is bad. Repair/replace it.

I got a 28 inch widescreen computer monitor the other day for just under
$325 after shipping. Added another 2 years of warranty to it for just
under $100 more (3 years total.)

I completely agree with this point.

In my experience, TVs just don't work very well as monitors, producing a
very coarse image, and very lately, prices of larger LCD monitors have
plummeted.

The OP's friend should get a larger monitor - the cost can be lower since
the speed won't really be a factor, but brightness should be considered.

-pk

 

[Ritter 197]

I was over at my friend to-day and worked for a while with his setup.

Eventually I called for him SHARP, His digital TV used as monitor is 32"
Aquos. Sharp technicians were quickly on the line and seemed technically
very savvy. After a number of tests and resets to factory defaults he came
to the conclusion that it was the inverter of the monitor. The guaranty
covers in house labor and parts and they will send someone out to Columbia,
MD. in the next few days. Sharp said they are highly confident they can fix
the problem, but if not, will replace the digital TV.

Thanks for all your suggestions.

Connect the monitor (digital tv) to your laptop and display your laptop
output on the external monitor (very few laptops I can think of cannot
hook to external monitors like this.) I am guessing he is connecting
using VGA or DVI - you should have at least a VGA output on your laptop -
use it and whatever keystrokes pushes the display to the external port to
test the monitor/TV to see if it is the problem or if the computer/video
card is the problem. Bring your own cables too - so you can make sure
that is not the problem.

If you verify the monitor still goes off connected to your laptop after a
short time - just like when connected to his desktop - you are done. The
monitor is bad. Repair/replace it.

I got a 28 inch widescreen computer monitor the other day for just under
$325 after shipping. Added another 2 years of warranty to it for just
under $100 more (3 years total.)

I completely agree with this point.

In my experience, TVs just don't work very well as monitors, producing a
very coarse image, and very lately, prices of larger LCD monitors have
plummeted.

The OP's friend should get a larger monitor - the cost can be lower since
the speed won't really be a factor, but brightness should be considered.

-pk