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Bad Display cable ??
HI
I reciently recieved a Latitude CPx 500mhz w/ 256 meg ram from work because it was always crashing. The first thing I found was a bad cooling fan which I replaced with no problem. But the next issue was a little trickier. It sometimes dies for no reason and at other times will run great for hours. The only constant is that if you tilt the display toward you it locks up instantly. I took it apart and inspected the ribbon cable. I could not find anything visible to the naked eye but I taped the wires in case there was some grounding out going on. After reassembling the unit it will not start at all, all of the lights flicker and stay on for a few secomds but then go out. With the exception of the HD led which only flashes for a split second. But after several tries it will sound like its booting , the Hd runs and the CD runs but no display. It should be known the when it would freeze in previous cases it would take several tries to get it to start. should the laptop start if i keep the display cable disconnected and hook up an external moniter? And could the display cable if internally broken or frayed keep the computer from starting??
It should be noted that I've had this unit 100% disassembled and working again before I messed with the display cable so the obvious question are answered, The memory,prosessor and boards are seated fine. I did discover that the screws that attached the display frame to the metal hinge were missing which possibly caused stress on the cable.
Any ideas are appreciated.
Rs1980t
Hi
It does work with the external moniter but will freeze if you move the screen. The cable is still attached to ithe laptop screen. The screen itself seemed OK , the only problem s were when moving the screen so that fosuses on the cable. Now the screen doesn't even respond so that means whatever fracture was in the wire is now broke. I'll post again after the cable is replaced . Thanks for you help.
Rs1980t
Hi Chris
The contacts are all the way in. The light on the screen is at about 5% if at all. It may just be picking up light from the lamp behind me. I can see the desktop if I shine a light on it. Is this the bulb or inverter and if so is the screen trash?
AussieChris
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Posted January 14th, 2005 02:00
Hi,
You may not have the cable in correctly to the invertor. It is the small card on the back that runs the backlight. It is a Zif ( zero insertion force ) type of cable. If you can see more 1mm of the contacts, this could be the case. It could even be the wrong side of the slide. Also, there is a plastic loop you can take out ( of the ribbon cable ), depending on LCD brand. Some had the invertor in a different place, so the loop was extra cable to reach. If you need the extra and dont have it the cable can pull out as you put it back together.
Regards Chris
AussieChris
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Posted January 14th, 2005 03:00
Hi,
A bad backlight is normally the LCD, I would try the old cable again, without the keyboard. If it still is faulty, it may be the LCD. Are you sure the cable connection is right ?
Regards Chris
AussieChris
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Posted January 21st, 2005 01:00
Hi,
Your having a bad run ! If the invertor is good, it may not be getting power. This can be the motherboard or the video card. If you have had a shorted cable, it may have taken out something else. I would reseat the video card first.
Regards Chris
HI Chris
If the motherboard or video card were bad would an external moniter still work ??
I assume that the inverter is on the back of the LCD, so that would lead to a defective unit. Are there any tests that I could run while on an external moniter to see is there was any board or xard damage.
Thanks
Hi
I'm back again. I purchsed a new LCD from a computer store on e-bay. And guess what ?? Same problem. The screen is dark with or without the keyboard connected. I've solved all other previous problems with crashing (its was a bad RAM stick) probably overheated before I put new fan/heat sink. It runs great on external moniter but still dark using laptop LCD. I contacted the seller to question possibility of DOA screen. Is there anything else that could cause a dark display ?? I can see the desktop with a light shining on it so it looks like the backlight is burnt.
Thanks
AussieChris
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Posted January 21st, 2005 03:00
Hi,An ext mon still may work, it may not have power going to the LCD invertor, rather than a logic type of problem. I have seen the fault caused by both. Not very often however.Regards Chris
AussieChris
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Posted December 19th, 2004 22:00
Hi,
Take the Lcd section off, and try with an ext. mon. If it boots, your problem is display related. You could the replace the cable, and try again. The cable may have rubbed on the back of the keyboard, so have a look there. Good luck.
Regards Chris