M.NT68676.2A lcd controller - brightness control

Choidebu

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So I had an old netbook which I gutted the screen and planned to create a standalone monitor out of.

The screen is 11.6", wled backlit AUOptronics made B116XW03 V.0.

I then ordered a controller board for it, which is the M.NT68676.2A. I asked the seller if it required an inverter (it shouldn't, not being a ccfl backlit, but figured I ask anyway) and whether or not I can sort of intercept the backlit duty cycle signal and control the brightness with a pot or something, since I don't want to use the included OSD and buttons.

Long story short I didn't find a definitive answer from them due to language barrier and me not willing to spend time explaining. They did say my screen doesn't need inverter.

B116XW03 datasheet

M.NT68676.2A datasheet

Looking at those datasheets it seemed trivial to purchase a pwm generator module (found a wide input one with 5V output and 2 pots to control freq and duty cycle) and just feed the pin 35 (CN5 pin 4 on the board) from it.

It's just 900Hz - 1.1KHz, duty cycle 5 to 100%, logic level 0.8 to 5.5V.

Anyone have any experience driving a wled backlit screen with COTS pwm generator module? Any thoughts appreciated, thanks!
 

Choidebu

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It lives!



Waiting for this TL494 based pwm signal generator to arrive in the mail.
 

Choidebu

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Did a hdplex/dynamo 160 pcie plug to barrell jack connector.



With this, it actually works like a laptop - turns on when the pc is powered and turns off when it's off. There were couple flashes of 'no signal', but for half a sec I don't mind it at all. Lucky since I thought it only turns on using the keypad. This way I don't need to use the keypad at all.
 

Choidebu

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Maybe not entirely related to this thread, but we've been using my salvaged monitor daily. When wife complained about tangle of cables and board hanging behind it, I decided to do something about it.

I melt a hole through my old laptop screen's frame, then mount the controller board using 15mm plastic pcb spacer:


Worked alright.


There's some tangled mess of wifi antenna cables there - was going to test connecting it to my onboard m2 wifi card, see if the reception is any better...

On a more related note, my TL494 is here since weeks ago, but I just noticed that there aren't any cable going from CN5's ADJ pin to the panel - but the brightness control OSD does work - so I figured the IC must have done it in software, outputting the signal somehere in CN25 (lvds connector).

Just need to probe the adjust pin on the panel side, see where it connects to on the controller... just never seem to find the time to do it.

Now, I'm thinking of giving up making a stand for it, and just mount the entire thing with a vesa mount to my S4M-C's side panel with this. Seems pretty tight with 20mm distance, which is the height of that spacer, plus pcb, plus solder points...
 
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Clem

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Nov 26, 2020
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Hi, does anybody know how to control the brightness on a M.NT68676.2A without the OSD board ? I can't find any information about the pin 4 on CN5 connector.
Any idea ? Thank you very much for your help !
Clem