April 27th, 2012, 02:07 AM
Gateway laptop w/faulty LCD
The mother-in-law brought me her Gateway NV57H13U laptop showing strange glitchy video on the LCD with weird colors and such. I opened the lid and found that slight pressure on the video cable at the LCD connector changed the glitch which led me to believe the cable or connector was bad.
I have done the following:
Checked video w/ external monitor - result: good video
replaced cable - result: video still corrupt
replaced LCD - result: no video, only backlight using either cable
Updated BIOS - result: no effect
The original LCD P/N is B156XW02 V.2 the replacement is B156XW02 V.6 (visibly identical). Google tells me that both versions were used in this machine. Any ideas why this new LCD would not work correctly in this laptop?
April 27th, 2012, 09:01 AM
The new LCD may very well be bad. Has anyone checked and confirmed it to be working?
You probably have a faulty solder joint somewhere in the old panel. Unfortunately fixing those is very difficult or almost impossible if you don't have a hot air rework station. With a bit of luck it's not a buried via in panel's circuit board - that would be next to impossible to fix.
Since the old panel is useless anyway you can try reflowing it. It is a *very delicate* procedure that requires an oven with precise temperature control.
Remove all plastic and paper accessories from the board, cables too.
Place the naked board over a tray using some improvised standoffs at about 2" high. One side may contain parts that are seemingly heavier than the other side. Place that side up. If one side has surface-mount connectors that side will be up.
1. Preheat oven to 150C (300F)
2. Once oven is at temperature insert tray with board.
3. Let it heat for 4 minutes
4. Increase the temperature to 200C (390-395F). Once it reaches the point wait 2 minutes.
5. Increase the temperature to 230C (445F). Once it reaches the point wait 1 minute. If you can't get 445 then use 440.
6. Decrease to 200C again. Wait 1 minute at 200C
7. Turn oven off. Opening door with a hot oven isn't ideal, but do it. Let it cool.
The temperature control is very critical (within few degrees!!!). Use a digital thermometer to check and don't open the door during the process. If the oven has it's own controls use them only as a reference unless you have an IR thermometer and can double-check that it actually heats to the set temperature, no more and no less.
Last edited by CeeBee; April 27th, 2012 at 09:29 AM.
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April 27th, 2012, 11:33 AM
I'm all for trying reflow (when the wife isn't home of course) but I may have a problem with the PCB configuration. I was going to swap PCBs between the new and old LCD but I gave up when I found 3 data cables soldered directly to the board between the PCB and LCD. My gut tells me these connections will be toast even if there is a way to remove them on the LCD end.
Here is a picture of the LCD I am dealing with. The data cables are barely visible through the "Don't Touch" sticker.
My oven has digital controls and I have an IR thermometer so I'm covered on that end.
Thanks for your help!
April 27th, 2012, 11:50 AM
Worst case you can re-solder the cable...
Thing is you have very little to lose (maybe time ). I've had some success with a video card, but only lasted few days before problems started developing again. If you have a convection oven you have better chances of success.
If it doesn't work from the first attempt try again and increase the peak temperature to 240-245C and keep up to 3 minutes. Under no circumstance exceed 250C.
Protected by Glock. Don't mess with me!
April 27th, 2012, 01:13 PM
Thanks CeeBee, but after a closer look I have decided against reflow. The pitch of the solder joints on the data cables are so fine it seems like assured failure if I desolder them. Even though this old LCD is junk it does give me a baseline with which to troubleshoot. If I destroy it I no longer have that.
I assume I am also out of options with the new LCD. I have replaced several of these in the past, occasionally even upgraded screen resolution in the process, but I have never had one just refuse to work.
I got the new LCD from ebay (brand new in OEM packaging) and I'm stuck with it since I'm past the return date. Any suggestions on what to do next?
April 28th, 2012, 03:48 PM
In so far as E-bay is concerned, I would try to contact the seller and negotiate a good replacement even tho the date is past due. You can offer positive feedback as opposed to negative feedback. That is worth a lot to the seller.
HP Laptop 6830s with 4 Gbs ram and a 250gb HDD I run Vista business 64bit.
But I have some old computers too.
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