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[Sticky] Composite LCD Controller Boards  

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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
01/02/2017 6:55 am  

I'm setting this thread up so we all can find the best composite LCD controllers.

I know that you guys are buying various 4.3" LCDs, and they all have different boards. I'm hoping everyone can post an image of your LCD controllers and a link to the place where you purchased the LCD.  

This is going to help people find LCDs to buy, and it will help people modify the LCDs they already purchased.

Here are the rules for this part of the forum:

  • Make only one reply showing your controller board
  • Show/explain what you did to get it to work at 5v using only the one reply
  • Please tell us where you got the LCD and when you ordered it
  • If anyone has questions, please start a thread outside of here. We need to keep this clean
  • Don't use this thread to ask for help getting your LCD working. Use the support thread.

The support thread is here:

http://othermod.com/community/hardware/composite-lcd-controller-board-support

Edited: 3 months  ago

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sonicmule
New Member
Joined: 4 months  ago
Posts: 4
02/02/2017 5:59 pm  

Here's my board in situ running perfectly at 5volts (buck converter removed).

Got it from eBay

http://www.ebay.co.uk/itm/4-3-TFT-LCD-Car-Rear-View-Reversing-Color-Monitor-DVD-VCR-For-Backup-Camera-/282213022333?hash=item41b534fa7d:g:0CIAAOxy3NBSoBm3

I did purchase another display, which worked ok at 5volts, but the display had a poor viewing angle.

Also, I found these config.txt settings got the best display on the 480 x 272 panel especially on the console screen.

disable_overscan=0

overscan_left=-14
overscan_right=-4
overscan_top=-16
overscan_bottom=-26

framebuffer_width=480
framebuffer_height=272

sdtv_mode=0
sdtv_aspect=3

 


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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
06/02/2017 2:18 am  

OK so I ordered a new LCD and it's different than any past ones, so here it is for you guys. I purchased a ton of these last week from a guy that isn't selling them anymore, so I can't give you a link.

This one does not work at 5v at all. It works differently than any I've seen before. The buck converter drops the voltage directly to 3.3v and skips 5v entirely. Normally in a situation like this, the board will still work at 5v because the buck can drop 5v to 3.3v just the same as it drops 12v to 3.3v. Unfortunately this buck converter is trash and cannot manage that. To top it off, there is no writing on the chip, so I can't even hunt down a datasheet.

I verified the 3.3v output by putting 12v to the board and using a voltmeter at the pins of the buck and at various points around the board (on the diodes and inductors mostly) to look at voltages.

Putting 5v to the buck would have fried the board. 

I ripped a bunch of components off to look at the traces and figure out the path of the power. I determined that the converter was indeed dropping directly to 3.3v, and that the output was going out to the inductor at the top (the round component labeled 100)

So here is the final result. The only component that actually needs to be removed is the inductor at the top right labeled 100. Taking it off will completely disconnect the buck converter circuit. Attach 3.3v to the part circled in red and attach the GND to the normal point as before.

To generate the 3.3v, you're going to need a buck converter. I'm currently designing one made for this purpose.

Edited: 2 months  ago

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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
06/02/2017 3:15 am  

Here is another one. I bought this one a long time ago and I don't remember where I got it from.

This one has another variation of the 1509, and it works a little differently than normal. This buck drops the voltage to 5v normally, so we just have to bypass it entirely

I verified the 5v output by putting 12v to the board and using a voltmeter at the pins of the buck and at various points around the board (on the diodes and inductors mostly) to look at voltages.

I looked at traces to figure out the path of the power. I verified that the converter was dropping to 5v, and that the output was going to the inductor at the top (the round component labeled 470)

So here is the final result. I recommend removing the inductor and 8-pin buck converter at the top right. I always remove the diode too because they are useful for other projects. Attach 5v to the part circled in red and attach the GND to the normal point as before.

Edited: 3 months  ago

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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
07/02/2017 6:36 am  

And another one. Can you guys tell that I've been working really hard to find an LCD I can stock? I'm sorry I can't give links for you to purchase these. I ordered most of these around the middle of last year.

This is another one with a junk buck converter that drops directly to 3.3v. 5v cannot be applied to this one.

The process starts by removing the inductor at the top right. It's the round one labeled 330.

Once the component is removed, you need to connect 3.3v to the pad circled in red.

To generate the 3.3v, you're going to need a buck converter. I'm currently designing one made for this purpose.

Edited: 2 months  ago

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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
07/02/2017 6:48 am  

This LCD is a little different from the others. The LCD is 50-pin instead of the normal 40-pin. Other than that it works the same.

This one drops 12v down to 5v using the standard 1509 buck.

The best move here is to remove the buck and the inductor (circle component labeled 101). As usual, I also removed the diode since the board doesn't need it anymore.

Attach 5v to the pad circled in red and you're up and running.

Edited: 3 months  ago

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othermod
Estimable Member
Joined: 7 months  ago
Posts: 146
07/02/2017 6:54 am  

One more, then I'm calling it a night. This one actually arrived completely dead and the 5v modification brought it back to life. I assume the buck was defective.

This is another that uses the 1509 buck to drop 12v to 5v. 

Again, the best move here is to remove the buck and the inductor (circle component labeled 101). I went ahead and removed the diode.

Attach 5v to the pad circled in red.

Edited: 3 months  ago

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dlarts
New Member
Joined: 3 months  ago
Posts: 1
10/02/2017 11:20 pm  

Hi,

this is my lcd controller board:

I ordered it from aliexpress.com but I noticed later, that it's resolution is only 320x240, so maybe I will order another one with a higher resolution. The buck converter on this board drops the voltage down to 3.3v, so I have to use a buck converter to convert from 5v to 3.3v. I removed some more unneeded components, the diode next to the +12v connection, the capacitor (47 35V VT) next to the diode, the buck converter and the coil (101) on the bottom left of the picture. You have to connect the regulated 3.3v to the old connection of the coil and then the lcd works fine with rasperry pi zero.

 

 

Finished mod:

Macro of the buck converter:

Edited: 3 months  ago

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