Replacing LCD

[Guest]

Archived from groups: comp.sys.laptops (More info?)

I'm looking for tips on replacing LCDs. I got a used Compaq Presario
laptop with no screen and seperately I got a used Compaq Presario 1200
screen. Physically, the two match, although I'm not certain of the
model of the computer -- it says 1456VQLIN on the back, but from
googling that it seems to correspond to a number of different Presario
models.

I assembled everything ok, the cables and hinges match up, but when I
power it on I just get a backlight with no image. Using an external
monitor everything looks fine.

Any clues on how I determine if this is a bad LCD, wrong model LCD, or
something wrong with the computer? Or maybe something I'm doing wrong?

Thanks,

- Mark

 

[Mike]

Archived from groups: comp.sys.laptops (More info?)

mviesel wrote:
> I'm looking for tips on replacing LCDs. I got a used Compaq Presario
> laptop with no screen and seperately I got a used Compaq Presario 1200
> screen. Physically, the two match, although I'm not certain of the
> model of the computer -- it says 1456VQLIN on the back, but from
> googling that it seems to correspond to a number of different Presario
> models.
>
> I assembled everything ok, the cables and hinges match up, but when I
> power it on I just get a backlight with no image. Using an external
> monitor everything looks fine.
>
> Any clues on how I determine if this is a bad LCD, wrong model LCD, or
> something wrong with the computer? Or maybe something I'm doing wrong?
>
> Thanks,
>
> - Mark
>

I'm a little confused. You talk about the LCD screen, but also hinges
which means the whole top section...but the number looks like an LCD number.

I just went thru this with two laptops. There are different interfaces.
There are different plugs on the same interface. There are different
cable lengths,pinouts even when the plugs are the same. I determined
that there's almost no chance of replacing the screen with anything but
the exact model screen. There are cases where the exact model screen is
used on different computer makes/models. There are different screen
technologies/sizes used on the same base model. Sometimes there
are switches or jumpers to tell the motherboard which.

Even in cases where you could swizzle things to make it work, the info
required is unobtainable. People who know what to do
want to charge you for doing it. There's no profit in them telling you
how. Vendor's won't even discuss the specs/pinout of a custom display.
I spent probably a hundred hours googling over the last six months.

I found my best source of info was ebay. Search for a screen or LCD
for the
laptop. Eventually, someone will post the screen part number or a
sufficiently detailed picture in their
auction. Then you'll know if it's what you have. If you're missing
the whole top section, you also have the problem of cables.

If you have to buy a screen off ebay, be VERY PATIENT. In my case,
new screens were $345. Typical used ones were going for $150-$250.
Probably bid on a fifty of them till it got one for $10.50 plus
$20 additional dealer profit (aka shipping in ebayspeak).

Patience has it's rewards.
mike

--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

X-No-Archive: yes

I got curious here. Is it possible that you did not connect the
data/display cable between the LCD assembly and the motherboard? Since
you got backlighting, I assume that you have the inverter working fine,
and therefore the problem is not getting "data/display" from the
motherboard.
Perhaps the display you bought/got did not have the ribbon cable with
it?



> > I assembled everything ok, the cables and hinges match up, but when I
> > power it on I just get a backlight with no image. Using an external
> > monitor everything looks fine.
> >
> > Any clues on how I determine if this is a bad LCD, wrong model LCD, or
> > something wrong with the computer? Or maybe something I'm doing wrong?
> >
> > Thanks,
> >
> > - Mark
> >

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

Just to clarify, the computer was just the bottom half, no "lid"
attached. I got the LCD with the whole lid assembly, including bezel,
hinges and cables. The way these computers are labeled, the model name
only appears on the screen bezel, which makes it hard to figure out the
model name of the computer section. The bottom of the computer shows
the 1456VQLIN label, which correlates to a number of different Presario
models, including the 1200, which is the model name on the screen
bezel.

>From other things I've read, it sounds like I'd have to take the screen
assembly apart to locate the LCD part #, but I still haven't found a
reference that would let me correlate that with compatible computer
models.

It's all pretty low budget, $46 for the bottom half & $51 for the
screen. Wouldv'e been quite a deal if it actually worked, but I guess
as a cheap desktop setup it's not bad either.

- Mark

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

Yeah, I guess I should have checked into this before I bought. It's so
simple to swap external monitors, I had no idea that this would be so
much more complicated...

- Mark

 

[Mike]

Archived from groups: comp.sys.laptops (More info?)

mike wrote:
> mviesel wrote:
>
>> I'm looking for tips on replacing LCDs. I got a used Compaq Presario
>> laptop with no screen and seperately I got a used Compaq Presario 1200
>> screen. Physically, the two match, although I'm not certain of the
>> model of the computer -- it says 1456VQLIN on the back, but from
>> googling that it seems to correspond to a number of different Presario
>> models.
>>
>> I assembled everything ok, the cables and hinges match up, but when I
>> power it on I just get a backlight with no image. Using an external
>> monitor everything looks fine.
>>
>> Any clues on how I determine if this is a bad LCD, wrong model LCD, or
>> something wrong with the computer? Or maybe something I'm doing wrong?
>>
>> Thanks,
>>
>> - Mark
>>
>
> I'm a little confused. You talk about the LCD screen, but also hinges
> which means the whole top section...but the number looks like an LCD
> number.
>
> I just went thru this with two laptops. There are different interfaces.
> There are different plugs on the same interface. There are different
> cable lengths,pinouts even when the plugs are the same. I determined
> that there's almost no chance of replacing the screen with anything but
> the exact model screen. There are cases where the exact model screen is
> used on different computer makes/models. There are different screen
> technologies/sizes used on the same base model. Sometimes there
> are switches or jumpers to tell the motherboard which.
>
> Even in cases where you could swizzle things to make it work, the info
> required is unobtainable. People who know what to do
> want to charge you for doing it. There's no profit in them telling you
> how. Vendor's won't even discuss the specs/pinout of a custom display.
> I spent probably a hundred hours googling over the last six months.
>
> I found my best source of info was ebay. Search for a screen or LCD
> for the
> laptop. Eventually, someone will post the screen part number or a
> sufficiently detailed picture in their
> auction. Then you'll know if it's what you have. If you're missing
> the whole top section, you also have the problem of cables.
>
> If you have to buy a screen off ebay, be VERY PATIENT. In my case,
> new screens were $345. Typical used ones were going for $150-$250.
> Probably bid on a fifty of them till it got one for $10.50 plus
> $20 additional dealer profit (aka shipping in ebayspeak).
>
> Patience has it's rewards.
> mike
>

Does this give you any clues?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=44907&item=6775592111&rd=1&ssPageName=WDVW
mike

--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

I do have the complete display assembly, with both cables. I had to
remove the keyboard to attach the cables to the motherboard.
Everything fits precisely and securely. One thing I'm a little
uncertain about is where the ribbon cable attaches to the motherboard,
while it fits perfectly, it looks to me like the ribbon cable contacts
are on the wrong side. It's hard to see, but it looks like the socket
may only have contacts on one side, but not the side that mates to the
ribbon cable contacts. Everything fits so precisely, it seems odd that
the cable would be reversed.

- Mark

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

This is very difficult from the situation that you are in. Some models
of computer were built by the mfgr. with different LCD panels,
NON-INTERCHANGEABLE, even though the computer model is the same (exactly
the same), and switching may require any combination of different
hardware (lids, hinges, brackets), cables (video card to LCD), firmware
(video BIOS), video board (which might be on the motherboard) and
configuration (jumper) settings. What you are doing can be extremely
difficult, even impossible, without one critical piece of information
that is probably lost forever: what LCD panel (such as "1456VQLIN")
THAT PARTICULAR computer originally had installed.

And, of course, your LCD panel or motherboard or video card or cable
(LCD to video card or motherboard) could also be defective.

This works best if you are starting with at least one complete and
working computer that you can at least test components on.



mviesel wrote:

> I'm looking for tips on replacing LCDs. I got a used Compaq Presario
> laptop with no screen and seperately I got a used Compaq Presario 1200
> screen. Physically, the two match, although I'm not certain of the
> model of the computer -- it says 1456VQLIN on the back, but from
> googling that it seems to correspond to a number of different Presario
> models.
>
> I assembled everything ok, the cables and hinges match up, but when I
> power it on I just get a backlight with no image. Using an external
> monitor everything looks fine.
>
> Any clues on how I determine if this is a bad LCD, wrong model LCD, or
> something wrong with the computer? Or maybe something I'm doing wrong?
>
> Thanks,
>
> - Mark
>

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

mviesel wrote:
> Yeah, I guess I should have checked into this before I bought. It's
> so simple to swap external monitors, I had no idea that this would be
> so much more complicated...
>
> - Mark

You need to go to Compaq's site and get the model #'s for the LCD which fits
your unit. See if the #'s match what you have. If not, see if you can find
out what the LCD you have is supposed to fit. Look up that model and try to
decypher the pinout to see if it's the same.

Yeah, it's a lot of work....

jak

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

> http://cgi.ebay.com/ws/eBayISA PI.dll?ViewItem&category=44907 &item=677...

It looks exactly like that, except on the back mine only has one fan
and also has a scsi port. I've looked at a number of other Presario
models, and they all look pretty much the same. Of the ones that show
a picture of the fans & ports, I haven't seen any that match mine.

- Mark

 

[Guest]

Archived from groups: comp.sys.laptops (More info?)

Thanks for the suggestion. I surfed the Compaq site for awhile, but
couldn't turn up anything.

- Mark