I've been an Arduiner for a few month, have managed to make a few things : LED playing, temperature sensing, 7segs, LCD display and serial comm.
Lately, although i have changed nothing (at least i think i haven't changed anything), my LCD display doesn't work anymore. Backlight is ok but it displays nothing, or fullfilled squares, or vanishing stuff, etc... I've checked the individual Arduino outputs with leds : seems ok.
So, what do you think ? Is the controller of the lcd dead (how could that happen) ? Can the origin be somewhere else ?
Ok, it was my idea too. It's no big deal, LCDs are quite cheap, but i'd like to take advantage of this, so :
is this happening often ?
what can be the origin ? i've not been very very delicate with it (direct contact soldering, wild & unwanted de/re/connexion, touching the back of the circuit with my fingers, etc...), certainly some shortcuts now and then, etc... Yeah, bad boy style. Maybe i went a bit too far ? I thought it was more "userproof".
Or is it badluck ?
what can i do now with it ? Use it a a beautiful and smooooth blue light ?
midel
P.S. : to help diagnosis, i should say it started a few days ago with some pixel columns not responding though they seemed to be alive from time to time.
What do you see if you connect the power, contrast, and backlight (pins 1, 2, 3, 15, 16) only - no Arduino involved except to possibly supply the power?
I did what you told me too, unplug everything but VSS, VDD, V0, LED+ and LED- what i get is :
sometimes nothing excepted the back light
sometimes the right 8 characters (on both lines, it's a 16x2) appear as full rectangles and then rapidly vanish and so i go back to above situation
To be perfectly accurate, on my setup, everything's not unplugged from the Arduino, as R/W DB0,1,2,3 are soldered to VSS and LED-. Do you think i should try without this common ground ?
Oh... I made the test with effectively unplugging DB0-3 and R/W from ground (but they are still connected together), and the result is a bit different :
I have the right side of the LCD characters displayed as in the second situation i described, but they do not vanish anymore.
Nothing special happens. Display may change or blink or fade a little bit, but i'm not sure whether it's because of me pressing on the bezel or me touching the contacts on the back of board.
Anyway, i'm still with the LCD right side characters fully ON, le left side OFF.
Does it help ?
midel
P.S. : typical situation. Right after plugging, i have the right side "ON". After a few minutes, a part of this right side dissappears/vanishes LCDprobleme
The right hand side of the display is controlled by a separate chip ("blob"/ "COB") to the left. If ever the two sides display differently, it indicates that either the connections between the two sides are defective, or one or other chip is defective. Apart from the Zebra strips as previously mentioned, this would be un-fixable.
It certainly looks that way. Luckily they only cost about $2 to $3, depending on where you get them from. OK, maybe $10 if you want to spend the money.
midel:
Any idea of how it could have happened ?
Now there's the question! This gets to the question of "counterfeit" or shoddy manufacture chips (and assemblies).
About 20 years ago (I think), I used to worry about cheap digital (LCD) watches that lasted less than a year. I wondered whether they were unduly susceptible to cosmic rays, or just poor manufacture. I do believe the chip densities nowadays are far denser, so it can't be the cosmic rays.
No, i think not - if it doesnt fall on the ground or you sunk it in water there is no reason to think, that it was your fault.
All those displays come from out the rolling manufacturing, without any quality tests or so and are very easy to use and not affected by "rough" handling.
Thanks for your reply !
there is no reason to think, that it was your fault.