laptop lcd, inverter,backlight,mother brd, cable,slp switch all ok but bump, it goes dark

[davidlaska]

All ok as stated in subject and external crt works fine while lcd will
go dark (still see the stuff as if the backlight died) if bumped. Do
not bump for hours, it works for hours. So I am left with some chip
or such on the lcd board gone bad. But why does a bump put it out?
It is not like wacking a tv set with cold crude solfer joints?
compaq presario 1500

 

[Meat Plow]

All ok as stated in subject and external crt works fine while lcd will
go dark (still see the stuff as if the backlight died) if bumped. Do
not bump for hours, it works for hours. So I am left with some chip
or such on the lcd board gone bad. But why does a bump put it out?
It is not like wacking a tv set with cold crude solfer joints?
compaq presario 1500

Could be a solder joint. Could be a poor connection. Could be anything.

 

[davidlaska]

I have the skill level of changing a few backlights on macs. Is there
any approach I could take for further trouble shooting (mechanical and
visual inceptions in particular)? I assume that the LCD solder joints
fail at times since I have seen others with the exact same problem and
computer.

 

[Meat Plow]

I have the skill level of changing a few backlights on macs. Is there
any approach I could take for further trouble shooting (mechanical and
visual inceptions in particular)? I assume that the LCD solder joints
fail at times since I have seen others with the exact same problem and
computer.

Ideally you would want to be able to lay the device out where you have
access to all the components and give it a good inspection under
magnification with lots of light looking for anything loose, poorly
soldered or cracked. Another thing that would be ideal would be where you
could power it up while it's laid out and tap around on the board(s) etc..
What would be helpful would be to be able to tap on it to get it to go out
and come back on. Hope you figure it out, it may take time and you'll
learn some valuable techniques in doing so.

 

[Jack]

All ok as stated in subject and external crt works fine while lcd will
go dark (still see the stuff as if the backlight died) if bumped. Do
not bump for hours, it works for hours. So I am left with some chip
or such on the lcd board gone bad. But why does a bump put it out?
It is not like wacking a tv set with cold crude solfer joints?
compaq presario 1500

I have come accross several LCD's that have one end of the CCFL tube wire
come loose. The solder has turned into very brittle material and resoldering
these has cured the problem.

JMK

 

[davidlaska]

Ideally you would want to be able to lay the device out where you have
access to all the components and give it a good inspection under
magnification with lots of light looking for anything loose, poorly
soldered or cracked. Another thing that would be ideal would be where you
could power it up while it's laid out and tap around on the board(s) etc..
What would be helpful would be to be able to tap on it to get it to go out
and come back on. Hope you figure it out, it may take time and you'll
learn some valuable techniques in doing so.

I will do visual stuff. I instinctively did bump it back on.
Rechecking the cable is very time-consuming. If I can find the
assembly for cheap, I might go that route. Since the external monitor
works, I can say that the problem lies within the top half of the
laptop?

 

[davidlaska]

One last question, since the lcd does show data but it is the
backlight that goes, can I confine my research to that only?
(inverter, cable, light)

 

[Meat Plow]

One last question, since the lcd does show data but it is the
backlight that goes, can I confine my research to that only?
(inverter, cable, light)

Yes.

 

[Meat Plow]

I will do visual stuff. I instinctively did bump it back on.
Rechecking the cable is very time-consuming. If I can find the
assembly for cheap, I might go that route. Since the external monitor
works, I can say that the problem lies within the top half of the
laptop?

More than likely

 

[davidlaska]

I have come accross several LCD's that have one end of the CCFL tube wire
come loose. The solder has turned into very brittle material and resoldering
these has cured the problem.

JMK

You guys have helped to narrow down the problem to cable between lcd
and inverter, and the inverter and CCFL tube. Before I commit to an
inverter, I like to find out if a screen that goes black and come back
in a cold or warm restart, is one the symptoms of a bad inverter.
I am down to two choices because if I go inside, I might as well put a
new CCFL in due to its age.

 

[Meat Plow]

You guys have helped to narrow down the problem to cable between lcd
and inverter, and the inverter and CCFL tube. Before I commit to an
inverter, I like to find out if a screen that goes black and come back
in a cold or warm restart, is one the symptoms of a bad inverter.
I am down to two choices because if I go inside, I might as well put a
new CCFL in due to its age.

Why not just shotgun it if the cost doesn't prohibit?

 

[davidlaska]

Why not just shotgun it if the cost doesn't prohibit?

I am not sure what you mean unless you are saying that the computer is
almost worthless. I looked on ebay after you mentioned cost and
realized that a 14" compaq presario 1500 with 250mb or ram and 30 gig
hd and pent 4 processor like mine sells under two hundred dollars.
So it is not so much the money now, but the idea of spending close to
that price on Ebay. ( i have purchased over five laptops throughout
the years on ebay and it has been smoooth ).

Is there a place one can find particular quarks about specific
laptops? Issues that do not make a recall list but should have?

 

[JW]

One last question, since the lcd does show data but it is the
backlight that goes, can I confine my research to that only?
(inverter, cable, light)

Pretty much, but there is also a signal from the panel controller that
functions as an on/off signal for the inverter, and usually +12V is
delivered to the inverter from the panel controller as well.

 

[Meat Plow]

I am not sure what you mean unless you are saying that the computer is
almost worthless. I looked on ebay after you mentioned cost and
realized that a 14" compaq presario 1500 with 250mb or ram and 30 gig
hd and pent 4 processor like mine sells under two hundred dollars.
So it is not so much the money now, but the idea of spending close to
that price on Ebay. ( i have purchased over five laptops throughout
the years on ebay and it has been smoooth ).

Is there a place one can find particular quarks about specific
laptops? Issues that do not make a recall list but should have?

I didn't mean your laptop was worthless. What I meant was that if the
ccfl and inverter weren't a lot of money to just go ahead and replace them\.

 

[davidlaska]

I do seem to be dilly dallying around here. I would have jumped on
your light and inverter solution if I had not read about the same
problem and same computer someone else had. They did not get the
problem solved, even with an additional wiring harness.
Here is the source to keep me honest (I could have interpreted things
in error)

http://www.laptoprepairguy.com/lapt...shoot-fix-laptop-video-problems/all-comments/

comment 163

Thanks again, my laptop is worth about 200 dollars, almost not worth a
major repair if it should come up.

 

[Meat Plow]

I do seem to be dilly dallying around here. I would have jumped on
your light and inverter solution if I had not read about the same
problem and same computer someone else had. They did not get the
problem solved, even with an additional wiring harness.
Here is the source to keep me honest (I could have interpreted things
in error)

http://www.laptoprepairguy.com/lapt...shoot-fix-laptop-video-problems/all-comments/

comment 163

Thanks again, my laptop is worth about 200 dollars, almost not worth a
major repair if it should come up.

That's why I suggested shotgunning the ccfl inverter and harness.

 

[davidlaska]

Something bad happened on top of all that, I bought a new memory
module and it only shows half the capacity.

So I am not happy about this laptop today.

 

[davidlaska]

The shotgun idea reminds be of a old laptop I had. I tried to get out
my frustration by peeling all the layers of the 12 inch lcd screen.
The last part was impossible, the two thin sheets of glass stuck to
each other. The best I have done is one inch by three inch tiny
display from a exercise machine.