Confused between different LCD2004 models

robmar
Posts: 6
Joined: Sat May 21, 2016 5:58 am

Confused between different LCD2004 models

Post by robmar » Thu Jun 23, 2016 2:42 am

Hello,
After successfully assembling an I3 PRO B kit equipped with the GT2560 board and the LCD2004 controller (white pcb), I've bought a second set of GT2560 and LCD2004 "compatible" controller (this time it came with red pcb) to be employed for an I3 aluminium version I'm planning to build using more accurate mechanical components.
The problem I've encountered is that on the new GT2560 / LCD2004 set the display doesn't work. After a closer investigation, it turns out that the pinout on the two 10-way connectors of the new (red pcb) LCD2004 display I got is not consistent at all with the GT2560 signals. For instance, the LCD connector of the GT2560 shows the power supply on pin 1 (VCC) and pin 2 (GND), while instead the LCD connector of the LCD2004 module is expecting power on pin 10 (VCC) and pin 9 (GND). The new display came with an adapter that transforms the two 10-way connectors to a single-row connector plus a smaller 4+4, but there's no place were I can fit it on the GT2560 board.
I'm completely lost... all the sellers of LCD2004 boards around specify that their modules are fully compatible (just a firmware upgrade, possibly) but I cannot see how a display can be considered "compatible" if the supply pins do not match? And, finally, how can I choose an LCD2004 display model that will be compatible for sure with my GT2560?

Many thanks in advance to anyone able to shed some light on this (at least for me) mysterious issue!
Roberto

Toy
Site Admin
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Joined: Mon May 16, 2016 8:40 am

Re: Confused between different LCD2004 models

Post by Toy » Thu Jun 23, 2016 10:14 am

Normally LCD 2004 is indeed compatible with GT2560, how do you connect the LCD with your board, can you post a picture?

robmar
Posts: 6
Joined: Sat May 21, 2016 5:58 am

Re: Confused between different LCD2004 models

Post by robmar » Thu Jun 23, 2016 1:32 pm

Hello, as per your request I'm attaching the picture of the connections layout board <> lcd, that's the straightforward standard one (EXP1 to LCD and EXP2 to SD)
20160623_062457.jpg
20160623_062457.jpg (158.69 KiB) Viewed 7899 times
But, as I told, the problem comes not from the connections, but from a major difference in the hardware of the two LCD2004 boards I have.
If you look at the schematic of the GT2560 http://www.geeetech.com/forum/viewtopic ... 18&t=16259) the supply pins of the LCD connector are 1 (VCC) and 2 (GND)
But since on the new LCD board I got (red pcb, from RepRapDiscount) I wasn't getting the expected voltage from the GT2560, measuring directly across the voltage regulator chip, I analyzed further and found that this particular board, although declared "compatible" has an LCD connector configured in a completely different way.
See the schematic http://reprap.org/mediawiki/images/7/70 ... scount.pdf where the supply pins on LCD connector are pin 10 (VCC) and pin 9 (GND)
No wonder I couldn't find the expected voltage on LCD board !!!
But now, since it is evident now that on the market are present two incompatible versions of the LCD2004, my concern is how to tell in advance, before buying a new one, if the advertised board will be of the first kind (supply pins 1-2) or the second kind (supply on 9-10) since all sellers are declaring them fully compatible, while, at least for what concerns the GT2560 board, they are not.
It is enough to look for a white-pcb display board to get the right one? Still confused...

Toy
Site Admin
Posts: 116
Joined: Mon May 16, 2016 8:40 am

Re: Confused between different LCD2004 models

Post by Toy » Thu Jun 23, 2016 6:00 pm

You are right, the LCD you bought is not compatible with your board, so it's necessary to figure out the the version of the LCD, as far as I know, white PCB and blue PCB is campatible with GT2560 board.

robmar
Posts: 6
Joined: Sat May 21, 2016 5:58 am

Re: Confused between different LCD2004 models

Post by robmar » Thu Jun 23, 2016 6:27 pm

Yes, as long as they don't start changing the solder mask color of the wrong model... ;)
Curiously enough, the vast majority of LCD2004 controllers available around is of the red type, but apparently no one encountered this problem before :roll:
I'll do some researching and post the results.

robmar
Posts: 6
Joined: Sat May 21, 2016 5:58 am

Re: Confused between different LCD2004 models

Post by robmar » Sat Jun 25, 2016 12:34 am

Good news!
've found a decent workaround to fix the LCD2004 incompatibility issue.
Being rather stubborn and don't giving up easily, studying the schematics suddenly it came to my attention the fact that the different pinout on the red board were nothing but the same configuration of the GT2560, only... mirrored! Thus pin 1 = 10, 2 = 9 and so on. Having discovered this, I've cut right away two new openings into the IDC ribbon socket's walls in order to accommodate the female plug reversed by 180°
board.jpg
board.jpg (225.63 KiB) Viewed 7850 times
And then, make it or break it, I've powered the boards and... bingo!
20160624_180426.jpg
20160624_180426.jpg (188.51 KiB) Viewed 7850 times
So, in the end, it turns out that the same board comes in two versions, being the only difference the orientation of the two 2x5 IDC connectors. Hard to tell where's the logic in it, but the positive fact is that the problem can be easily solved with a pair of clippers!

shadowcaster
Posts: 18
Joined: Sun Jul 10, 2016 8:44 pm

Re: Confused between different LCD2004 models

Post by shadowcaster » Thu Feb 23, 2017 2:34 am

Thanks a lot!

Chamarejc
Posts: 3
Joined: Sat May 06, 2017 11:38 pm

Re: Confused between different LCD2004 models

Post by Chamarejc » Sat May 06, 2017 11:43 pm

Hi,
Thanks a lot for your help.
After an half day trying to understand what's happened, your solution solve my problem in five minutes.
Now my LCD runs.

pochacz
Posts: 0
Joined: Sun Jan 21, 2018 10:32 pm

Re: Confused between different LCD2004 models

Post by pochacz » Sun Jan 21, 2018 11:03 pm

Hi, i was long time since last post, but i haw similar problem, recently I bought Geeetech Prusa i3 Pro B 2017 model, the LCD is not working ( no beck light or anything on it ) however after spinning the knob i can see led blinks on the GT2560 board so they are connected some way, the only difference between my LCD and the one in that post is that my pcb is green, so my question is will that fix work for me??

cobraoffroad
Posts: 0
Joined: Sat Feb 03, 2018 5:41 am

Re: Confused between different LCD2004 models

Post by cobraoffroad » Sat Feb 03, 2018 5:43 am

I have the same problem did it you try it and has it worked?

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