How to use an LCD backlight as a light table? - Page 1
Forum section: electronics / projects

author: Rodast
author_rank: Contributor
timestamp: September 08, 2013, 01:21:35 pm
content: Hello All,cleaning up my basement I found my Dad's old notebook who's LCD once got cracked on a flight when someone tried to crush his case into an already overcrowded compartment.I took it apart to see what could still be useable and am quite fascinated by the LCD backlight panel after I removed the LCD glass front and would like to use it as a light table.The backlight itself only hast two cables but I already figured that these are no DC inputs.I also have the LCD Inverter module that came out with the LCD which seems to be supposed to convert DC to AC in the fashion needed by the LCD.But the connector on the inverter (two pin to the LCD and 8 to the DC side) is more complex.How can I figure out how to power the Inverter module to convince the LCD backlight turning on? Or is there a simpler way of doing this?LCD:Samsung LTN141X8-L00IBM P/N: 05K9677FRU PN/: 05K9678Inverter:P/N: 12P3050FRU P/N: 12P3051EC F80841*1Z23T386166*I attached some pictures of the inverter board with the two pin LCD connector to the right and the 8 pin to the left.Quick links to full views of imageshttp://picload.org/image/ooailra/bottomboardleftd.jpghttp://picload.org/image/ooailrl/bottomboardright.jpghttp://picload.org/image/ooailri/bottomboard.jpghttp://picload.org/image/ooailrw/topboardleftdeta.jpghttp://picload.org/image/ooaildr/topboardrightdet.jpghttp://picload.org/image/ooailda/topboard.jpgAny ideas how to get this powered up?Best regardsRodast

author: adam1213
author_rank: Regular Contributor
timestamp: September 08, 2013, 01:33:35 pm
content: Note: some backlight inverters will power backlights at high voltages from a lower input voltage. e.g. use caution.Try applying power to the board. As for where to apply power and the required voltage(s)One way of determining this is to look at the datasheets for the ICs to work out the where to apply power.VCC likely goes through F1.Datasheet for a SIMILAR IC to one found on the board (note the pinout may differ between the B and ema versions) -http://astro-foto.astronomie.cz/mp1010bem_909.pdfAnother IC: LM393 (Dual Differential Comparator)Most laptops have the ability to control the LCD brightness. This may mean that the board needs to be told to set the backlight to a given brightness in some way. e.g. look at the datasheet for the mp1010 as may be used to control the brightness.

author: mariush
author_rank: Super Contributor
timestamp: September 08, 2013, 01:49:26 pm
content: The voltage on the lamp is 700-1400v .. be careful.Rather than messing with that custom inverter, you could order an inverter from eBay... i've bought a few and they work just great:http://www.ebay.com/itm/Universal-CCFL-Inverter-LCD-Screen-Inverter-Board-10-28V-4-Lamp-for-15-22-LCD-/350853611858?pt=US_Monitor_Replacement_Parts&hash=item51b0814152This one is designed to work with 4 cfl tubes, that 14" one may only have one or two cfl tubes.Here's one that's designed for only one:http://www.ebay.com/itm/Universal-LCD-Monitor-Inverter-1-Lamp-CCFL-Inverter-for-15-TFT-LCD-Monitors-/141047654073?pt=US_Monitor_Replacement_Parts&hash=item20d71866b9You basically feed it at least 10v DC and the controller generates the high voltages required for the lamps.

author: Rodast
author_rank: Contributor
timestamp: September 08, 2013, 01:58:34 pm
content: This looks tempting.I might be better off with one of those boards at my current level of experience.I figure it would be best to make a wooden frame for the whole installation to make sure not to get toasted.As I understand the difference between the boards are the numbers of connectors. So if my board only features one connector my backlight only has on lamp, correct?But a board with two connectors will also work?Best regardsRodast