Felix 2 LCD Backlight?

[angryangel]

the firmware in the download works also but you ave to use Arduino Mega 2560 or Mega ADK' borad for upload insted of the Arduino Mega(ATmega1280) witch is showen in the assembly instrucktion

[matteej]

do you have to insert an SD card before the display starts displaying stuff?
mine does nothing

[Danny-Lelystad]

Try to adjust the contrast with the little blue poti next to displayconnector, turn to the right slowly until u see the text. See pictures on this forum:
http://fablabdronten.freeforums.org/fel ... en-t3.html
(its in dutch, but picture is enough to see which connector in which direction)

[matteej]

The picture was a big help in orienting the wires
The LCD started working after pressing the big red reset button, and turning the pot-meter ALL the way clockwise.
Thanks for your help

[Kentxu]

Have installed the display, but it does not appear to be working. Just get 1st and 3rd line of squares:

Have tried adjusting pot, and updating firmware with no improvement.
It appears that there is a backlight in the pictures on this post, but not working either.

Any other ideas on what I can try?

Thanks, Ken

Update:
Found that the wires were loose on the display screw terminals. Tightened screws and now have backlight, but still no display. Just 2 rows of squares as above.

Help!!

[Kentxu]

I have checked all display screw terminals tight, updated firmware and adjusted pot.

Still no solution to this, so got out the oscilloscope to check signals. This is what I get on the screw terminals of the display:

Pin Name - Signal
1 VSS - 0V
2 VDD - 4.8V
3 VO - 0V
4 RS - Waveform "In 1" below (pulses low at 3.6ms period)
5 R/W - Low
6 E - Waveform "In 3" below
7 DB0 - Low
8 DB1 - Low
9 DB2 - Low
10 DB3 - Low
11 DB4 - Waveform "In 5" below
12 DB5 - High
13 DB6 - Waveform "In 7" below
14 DB7 - Waveform "In 8" below
15 A - 4.8V
16 K - 1.5V

This pattern repeats once a second (approx).

So there's activity on RS (data/ instruction), E (looks like a clock), and DB4,6,7. No other signals.

Is this what I should expect?
Is there any info on how the display should be wired so I can check if the ribbon cable is correct?

Any help appreciated!

Thanks, Ken

[seaton]

when I received a replacement LCD module after the problem with my backlight, it did exactly the same as yours,What I did to rectify was go check all wires going into the CLD terminal strip but gently tugging on them, then I tighten all the screws as a couple where loos from the looks of the screw positions on this terminal strip and this resolved it, now my LCD and backlight are working with no problems My original fault appears to have been a faulty backlight on the LCD module.

[Kentxu]

Thanks Seaton and Danny for the suggestions.
It's been a long slog, but I'm finally there! Working Display

It seemed unusual to me that there was data on D4,6,7 but not on D5. After looking through the Arduino code in the PINS.h file I found that the display uses these pins:
#define LCD_PINS_RS 16
#define LCD_PINS_ENABLE 17
#define LCD_PINS_D4 23
#define LCD_PINS_D5 25
#define LCD_PINS_D6 27
#define LCD_PINS_D7 29
So there should in fact be data on D5; off with the oscilloscope for more debugging; no signal on the connector or tracks, but a signal on the microcontroller pin.
Could it be a dry joint? Under the microscope this was what I found:

A touch with the soldering iron and flux fixed that. Plugged the display back in and now no backlight!!
I must have blown the LED, so opened the display module and mounted 2 new LEDs in the holes next to the old blown one.
Had to file the corners off the LEDs to fit them in. OK, the backlight is not as uniform, but it works

So finally there! Here's it all working:
http://www.youtube.com/watch?v=MQPPbHEEsIg

Now don't get me wrong. I'm very happy with my Felix. It does a good job!
But I think there are some quality issues that need to be addressed:
1. The microcontroller had a dry joint on a corner pin. AOE should have picked this up, or a test of the display connector.
2. Several screws were loose on the display ribbon connector. These should be checked.

Happy Printing! Ken

[Danny-Lelystad]

If i check the display connector on the Felix 2.0 pcb i get on all datalines (D0-D7) signals, see below:

8-channel logic analyzer on D0-D7 from the displayport at a Felix 2.0 pcb

[Danny-Lelystad]

Thanks Seaton and Danny for the suggestions.
It's been a long slog, but I'm finally there! Working Display

Happy Printing! Ken

Good to see u found the problem Ken. And you are right about quality control, this display should never be sent to u.