"Home made" LVDS controller board - Page 1
Forum section: electronics / projects

author: Darximor
author_rank: Contributor
timestamp: March 18, 2019, 08:43:21 pm
content: Hello,Recently, my old TFT monitor die (Turn on for a second with a weird sound then it's going in stand by), two capacitors maybe blownAnyway, keep this monitor broken was not worth it, so I decided to take it apartI noticed that the driver board is verry similar to controller boards used to reuse screen of broken laptop, luckily the connector was the same as you can see in the second pictureThe questions are :-How to power the board (Because I'm pretty sure that this is the internal power supply of the monitor that failed), and more precisely what is "adj" ? (on the third picture)-How to power the inverter of the laptop screen ? (the screen of the monitor was backlight directly from the power supply I think, according to the first picture)Thank you

author: jaycee
author_rank: Regular Contributor
timestamp: March 18, 2019, 11:29:56 pm
content: ADJ is probably for adjusting the intensity of the backlight

author: Darximor
author_rank: Contributor
timestamp: March 20, 2019, 02:02:03 pm
content: Okay so I don't need to take care about this pin because this is the job of the inverterHow do you think that the on/off pin work ?

author: kjr18
author_rank: Regular Contributor
timestamp: March 21, 2019, 05:50:57 am
content: Do you have a pinout for this screen inverter? If no, you should search for it, you will need it. You might need both 5 and 12 volts to power a logic board, on off and adj pins might be needed for your laptop screen inverter as well, considering if it's this way to drive it.

author: Berni
author_rank: Super Contributor
timestamp: March 21, 2019, 06:34:12 am
content: Well if the PSU is dead then you probably also won't get it to power the CCFL backlight.So you need to fix this PSU or buy a PSU that can run the CCFL tubes and another PSU that can supply the CCFL driver with DC voltage as well as make the correct voltage for your LVDS driver board.PSUs tend to use jelly bean parts so they are easy to fix if you know what you are doing. But don't attempt that unless you are experienced with mains voltage stuff, you can get some serious shocks out of it.

author: kjr18
author_rank: Regular Contributor
timestamp: March 21, 2019, 07:10:02 am
content: Quote from: Berni on March 21, 2019, 06:34:12 amI think that op wants to use logic board to drive a lcd from notebook. Regards repairing power supply, those two caps on the down right seem a bit bulged, so these two would be first ones to check/replace.

author: Darximor
author_rank: Contributor
timestamp: March 23, 2019, 09:51:26 am
content: I searched for the pinout or schematics and I was not able to find it for this particular model, but I will make further search for a generic inverter pinout compatible with this screen. Another option would be to use the dead motherboard of the notebook to power the screen light.Yes, the PSU is dead because of the two bulged caps on the down right (I think), maybe it's a bad idea to take risk trying to replace them because of high voltage. Furthermore I wanted to make my own case for this screen and I don't really know how to make it safely for this PSU. But on the other, hand what better than the original PSU ?And yes, that's exactly what I wanted to do, use logic board to drive a lcd from notebook

author: Berni
author_rank: Super Contributor
timestamp: March 23, 2019, 01:47:52 pm
content: You can buy 12V CCFL driver modules from ebay, but you probably need to get roughly the right wattage one.But if you are reusing laptop screens its best to pick ones with a LED backlight. Easy to drive with just a DC voltage and they are much more efficient (Less heat, less power draw, more brightness)

author: kjr18
author_rank: Regular Contributor
timestamp: March 24, 2019, 08:39:13 am
content: Quote from: Berni on March 23, 2019, 01:47:52 pmReplacing this one with led backlit one doesn't help much in this case. In LED ones you have both power and data on one connector, this would require another logic board capable of doing this.Replacing those two caps is not really hard, and does not involve any high voltage, as they are on low voltage side, and stupidly placed just above two rectifying diodes heatsink. So after some years electrolyte in these caps dried out. Just replace them with ones with the same capacity, and at least the same voltage. And make sure they are low ESR.I found out some info on these lcd screens, and I think you might need to reconsider the whole thing. Your old lcd has 5V power supply, and 2 channel 8 bit interface, and your laptop screen is 3.3V, 2 channel 6 bit interface. You can find this informationhereandhere. This site has a lot of useful info, good to keep it in bookmarks.

author: Darximor
author_rank: Contributor
timestamp: March 26, 2019, 10:21:01 am
content: Thank you kjr18 for these heplful link, so il believe it will be really difficult, more than I thinked according to these infosSo I will try to replace these two caps and see what happend