NEED HELP ON UNIVERSAL MONITOR CONTROL BOARD

[CJESO]

I am not really an expert when it comes to this, so I have to ask you guys in this forum for help. I have recently bought a universal LVDS LCD monitor control board and I don't quite understand how to power it up. I have attached a screenshot of the product below. Basically, for power, it has 6 pins labelled: GND, GND, +5V, +5V, ADJ, and BL. I have no idea what BL and ADJ means and how to power it up. Should all pins be connected for it to work? Or should I only use some of it? A detailed look of the board is also attached below. It'll be much appreciated if any of you guys can provide some assistance. Cheers!

[RTX 3090]

I think BL is backlight and ADJ is some sort of adjustment maybe for the contrast or LED power

[RTX 3090]

7 minutes ago, CJESO said:

Should all pins be connected for it to work?

Just the LCD should work without BL and ADJ, meaning no light. Shine a flashlight at the LCD and check if you can see any signs of life

[mariushm]

Yeah, BL is backlight.  Probably backlight enable/disable.  

ADJ is probably a PWM signal to control brightness/intensity of the backlight.

 

You also have some jumpers on the board, labeled A to H ... you can see in your picture on the back it says which jumpers have to be set and which don't, to match the lcd panel resolution and color depth.

 

[CJESO]

1 minute ago, mariushm said:

Yeah, BL is backlight.  Probably backlight enable/disable.  

ADJ is probably a PWM signal to control brightness/intensity of the backlight.

 

You also have some jumpers on the board, labeled A to H ... you can see in your picture on the back it says which jumpers have to be set and which don't, to match the lcd panel resolution and color depth.

 

So how should I power it up? what should I do?

[CJESO]

7 minutes ago, RTX 3090 said:

Just the LCD should work without BL and ADJ, meaning no light. Shine a flashlight at the LCD and check if you can see any signs of life

@RTX 3090 what should I do then to power it up?

[mariushm]

Set the jumpers to the LCD panel resolution.

Figure out if the panel is 5v or 3.3v  - there's a jumper for that as well on that board.

 

Power the controller board with 5v or 3.3v and ground from the power supply.

 

The LCD panel has either LED backlight  or CCFL (fluorescent tube) backlight. 

In computer monitors, the backlight driver is on the board with the power supply, so you connect the ADJ and BL wires to the power supply board, because that's where the driver is.

If it has LED backlight and you don't have a monitor power supply, you need a LED driver board.

 

Here's an example of such led driver board: https://www.ebay.com/itm/353130690186

 

A similar board here : https://www.ebay.com/itm/164487859570

 

You can see in the picture that it has an ADJ pin  (the ADJ on your display board)  and an ENA pin (which is probably your BL pin)

This particular led driver works with 10..28v and most likely you want to power this with 12v...16v

It seems to be a BOOST driver, which means it will output some voltage between input voltage and 165v, whatever voltage is needed to reach the set current.

For example, if the backlight of the monitor is uses groups of 10 x 6v 30mA leds in series, and there's 3 such groups of leds in a strip, you want to set the current to maximum 90mA (3 groups x 30mA max = 90 mA max)

You adjust current by soldering or desoldering resistors on that strip on the bottom.

The datasheet of the panel will tell you what backlight it uses (voltage and max current)

 

 

 

If the LCD panel uses fluorescent / CCFL backlight , you need a CCFL backlight driver, here's an example : New LCD Monitor CCFL Backlight Driver Inverter Board Boost 2 Lamp 12V Universal | eBay

 

Another version (2 or 4 tubes option) : https://www.ebay.com/itm/182639959158

 

Same story as the other .. these are typically 10v..28v input but will work best with 12..18v input  (vin and gnd)  and you have your ADJ pin and the ENAble pin (the BL in your board)

 

[CJESO]

@mariushm Thank you so much for that info. The board I have gotten is a 5V board. However I still don't get how to power it up. I have seen a YouTube video (link here: https://www.youtube.com/watch?v=M_0R5JmGrEc&t=304s) and from that video, he didn't seem to use any other board that you have mentioned. And I am planning to do the same thing he did in his video since we both have the same problem. I just have to connect the universal control board to the monitor but I don't know how to power it up.

[mariushm]

At 3:05, you can see the lcd panel has CCFL backlight, and uses 4 fluorescent tubes for the backlight, so if you have the same panel, you need a CCFL led driver with 4 connectors,

In the picture below I circled with yellow the connectors for the 4 lights, in orange you have the "backlight driver board" section. just because it was there, i also highlighted the headphones amplifier section but you can ignore that.

 

 

At 3:15 it tells you to determine the resolution of the panel and set the jumpers so that the resolution the board outputs matches the panels resolution

 

At 4:30  he takes out the wires it needs from the original cable between the power supply and the original display board. He takes out 5v , ground , backlight and probably adjust (though the text on video doesn't say)

At 5:17 you can clearly see 4 wires from the power supply to the display board - since the backlight controller is integrated in the power supply the BL and ADJ wires are routed to that connector.

The connector on power supply has more wires because it would also have stereo left and right and ground for the audio amplifier (display board can receive audio through hdmi and sends the audio to the audio amplifier so that if you have headphones you can listen). There normally is printed text near the connector or on the other side of the pcb saying what each pin does.

 

 

 

[CJESO]

@mariushm I have the four connectors for the backlight attached to the power supply. So I guess I wouldn't be needing the "backlight driver board" that you have mentioned.

 

Here is a picture of the labels in my power supply.

 

I can see the two +5V but there is only one GND wire although there is another GND wire on the top side, so maybe I can use that one? And I do not see any labels indicating BL. could it be the one labelled "ON/OFF"? This is the part I'm stuck at.

[mariushm]

 

The backlight driver board is incorporated into the power supply - you can see the two cables coming from the backlight of the lcd panel on the right side of the first picture.

 

See picture above ... you have ground , 5v and  DIM (adjust brightness, so most likely goes to ADJ pin on your board)  and ON/OFF which probably goes to BL \

 

You also have two GND pins all the way to the top.... all the GND pins are connected together so it doesn't really matter which one you use.

 

So it should be pretty obvious how to connect your board to that power supply.

 

[CJESO]

Really appreciate it man. Thank you so much for helping out. I am not really good at these kinds of stuff however I am learning. I didn't hook it up in the first place since I had little knowledge about it and was afraid of damaging the boards. Now that I knw which pins goes which, I can finish repairing this monitor. Cheers!

[CJESO]

@mariushm I recently bought another control board and I don’t get the jumpers on the board. Do you mind helping out?

[mariushm]

You figure out the panel's resolution ... let's say it's 1920x1080  

Then you figure out if the panel is 8 bit, or 6 bit + frc or whatever - that's what I THINK the numbers refer to. 

 

So if your panel is 1920x1080 8 bit then I would guess row 1 would be a valid configuration. 

That means set jumper on A and B   (put a jumper across the two pins to the left of letter A , and a jumper across the pins to the left of letter B)

If your panel is 6 bit, then row 2 seems like it would work - that means jumper on A pins and on C pins.

Remove the OC passed green sticker to see what other resolutions you have there.

 

As another example, if the panel is 1366x768 8 bit, then row 6 seems right, and that means only jumper on B is needed.