LCD display burns

Hi, I’m Andoni and I’m working my Final Project.

I worked properly with this LCD from DX.com until I moved it and its hardware while it was working. I don’t know what happened or what I could did but since that I can’t make it work as before. Only the characters from the right appears, and after few minutes they start to disappear. I tried with another LCD (but without Buttons) and it works properly. Maybe could i replace another LCD in the same shield with buttons??Anybody has this problem before? After being one month waiting for a new one, I burned it in only one day…I can’t understand but I’m sure I’m doing something wrong.

The connections are obvious: DB4-DB7 to pin 4-7 for data, RS and E to pin 8 and 9. Gnd to ground and Vcc to 5V after a power button. pin A0 to detect select,up,down,right and left buttons, and A1 to detect Reset.

Thanks.
Antxoni

With the information you provided I cant tell if its dead already but.. for sure you can get this LCD module out of the shield and solder a new one as it seems to me from the photograph as a typical 16x2 Hitachi driver display. but if the other LCD works fine with the same code then maybe you did something wrong with it try recalling any over voltage input to the shield.

If you're in a hurry you can probably find a vendor that can deliver a new one quickly. They cost about as much as a sandwich. I wouldn't waste time troubleshooting a $6 display.

Your photo is over 2Meg in size so I won't be downloading it but...

have you read the 'Warning...' sticky at the top of the forum page? I have to admit that I haven't read it all but it looks like your display is similar to the ones discussed on there?

And I have to agree with what raschemmel says - they aren't worth the effort if they suddenly stop working for no obvious reason. Put it in a drawer until you can have a play around with it.

Hi pisoni, and welcome.

I've been using this display for about a year now. Exact same setup from DX. My display was DOA, so i ordered a single display from DX (the few bucks isn't worth the hassle). I soldered that in and it had been flawless since.

But let me ask you this: Why did you put screws through those holes, and did you use spacers between the PCB's ? And why are you not using the shield as a shield, but put them next to each other ? The shield has solder pads for the pins it doesn't use for itself. And you are using the same pins as the shield does, so you didn't reassign any pins. Why the 4 wires through one of the holes that are also in the UNO ?

As i read your story, you had a defective display, and after replacing it and running it for a short time that 2nd one now has the same defect ? In that case do assume you did something wrong. But i can't tell what.

I could guess you might have a power issue. That might have done damage to a memory component, destroying half of the available characters (still guessing here, i'd expect lines to be gone, not 2 x half lines). Are you sure you're powering it with exactly 5 volts ?

Put it in a drawer until you can have a play around with it.

No , don't do that. Go get a hammer. Take the display and throw forcefully on the ground and swear at it. Now smash it to pieces with the hammer. Now that you got that out of your system you can forget about it and go back to work. SAFETY TIP (DON'T FORGET YOUR SAFETY GLASSES BEFORE YOUR SMASH IT WITH THE HAMMER ...)

That might have done damage to a memory component, destroying half of the available characters (still guessing here, i'd expect lines to be gone, not 2 x half lines).

A 16x2 has two ICs or two epoxy blobs on the back one of which is the HD44780U or equivalent controller. It contains all of the memory and enough I/O circuitry to drive the left half of this display.

The second IC or blob is the HD44100 or equivalent auxiliary controller which has the I/O circuitry to deal with the right half of this display. Displays with more characters have additional auxiliary controllers. All the details can be found by following the [u]LCD Addressing[/u] link at http://web.alfredstate.edu/weimandn.

It looks like the connections between the main controller and the glass are defective. I'm cheap so I would tinker with the bezel tension before getting out the hammer. Maybe just remove those screws....

Don

Right, raschemmel.

But before you start that, suit up. Safety shoes, long trousers, overall, gloves, helmet with face mask, the works. Just to be sure, have a fire blanket, powder extinguisher and large tub of water at hand (don't forget to check you have some ice packs in the freezer). Check you have 911 (or 112, whatever is right where you are) under quick dial and that that works. Have someone come over 5 minutes (synchronize your watches !) after you plan to start the demolishing of the display and let them bring a recently approved first aid kit (or have that available).

Thanks floresta for explaining that.

Right, raschemmel.

But before you start that, suit up.
Safety shoes, long trousers, overall, gloves, helmet with face mask, the works.
Just to be sure, have a fire blanket, powder extinguisher and large tub of water at hand (don’t forget to check you have some ice packs in the freezer).

LoL that person is crying with his LCD and you ppl have possibly every way to throw at him a giggle.
rather than smashing everything with closed eyes I would say hack the display and see how it works! learn from even the thing thats <= shit

Hi Andoni...

For what it is worth, here's some advice...

It may very well be damaged. BUT, since it's considered a loss at this point then I agree Ni$hant--Fiddle with it and see what you can possibly do in a repair attempt for just 20 mins. I've had problems with my displays before (some cheap & some not so much so) and I have fixed them so far. I was fortunate though, no static discharge had damaged the controller board. I've had my displays do this and it ended up being either dirt between the pcb contacts and the soft conductors internally or the whole metal bezel was improperly fastened at the factory so that it became loose in the mail during transport. This caused uneven pressure on the display and it couldn't function properly.

The instructions I am sharing are easy enough to follow, but take patience--this can't be rushed because you have to take care to re-align everything and this takes time. Also, don't do this to a perfectly working LCD display, there's just too much that can go wrong and if it's expensive then you'll be at another loss. Also, please read this all-the-way through before trying it at your own risk.

[u]THE GOAL:[/u] To carefully remove the rectangular, metal bezel off of the glass lcd panel while wearing some neoprene, nitrile or latex gloves. Wear gloves to prevent any grease from getting on the contacts and the two soft conductors underneath. We'll then clean the contacts and reassemble it with even tension.

Here's how to do this: 1. Bend the retention tabs of the metal frame so that they are straight enough to go back through the anchoring slots in the pcb. These are on the back of your lcd shield pcb. Use needle-nosed pliers or jewelers crimping tools to do this. Exercise caution so that you don't damage or nick any components.

  1. The rectangular metal frame can then be separated from the glass unit by lifting it away from the pcb. You will then be able to remove three additional pieces: the glass lcd unit along with two spongy conductor units. These spongy connectors work by conveying the signals from the pcb to the lcd glass display. I would handle those with care and as little as possible. There must be absolutely no contaminants between the pcb contacts and the conductors and there must be adequate, even pressure all along the display's bezel pushing down on the glass. If the pressure that is exerted on the glass is uneven, you will get nothing on the display or perhaps corrupt display data in some areas. Also, too much pressure on one side will give the appearance of what you are seeing... way too much contrast on one side and not enough on the other. >>See my note at the bottom of this post about contrast settings BEFORE you take this apart, if you do.

  2. Clean the conductors and the pcb contacts with pure alcohol or zero-residue cleaner. I used Perfect Glass on a cotton swab. I've read that others have had success with pure mineral spirits. The point is, you need to remove any grease, dust or buildup that could be on there. Do not saturate the equipment or the conductors.

  3. Take the time to clean the display while you have it out.

  4. Re-assemble but this time, put tension on the metal bezel a little at a time much like you put on car tires. Start at one corner and then go to the opposite corner next; then work your way around. When you put sufficient pressure on it, bend the tab inward a little and try to match that pressure and bend as much as possible on the other tabs as well.

  5. See if it works. Plug it up and run a sketch from the Arduino.

Additional notes: It goes along with common sense that you don't reassemble this unless it's absolutely dry after cleaning. Also, one display of mine fought me hard on the re-assembly. I couldn't get the tension right. The way I got it to work was by having my arduino sketch running and using the display while I reattached the bezel. That allowed me to see just how much pressure I needed to apply all the way around. It worked very well (though risk of shock) because the bezel turned out to be out of square and the tension had to be different on one corner than the others. I wouldn't have known if I didn't have the power running to it when I fixed it. You will know the pressure is good when the display characters appear as they should with proper contrast (make sure to check the contrast setting on the shield [u]BEFORE[/u] you start this process or you could be trying to see an image that will never display due to too low or high of a setting).

Good luck. I hope this helps you or someone else and saves you from the trouble I had with my displays. Please follow safety guidelines and don't get yourself cut, burned or shocked.

lot of thanks!!!

I’ll follow your advice, after getting my individual protection equipment!

I wish I had that much patience. I threw away a display with the exact same symptoms as the OP.

If you find that it isn't broken and that it just needed to be re-seated, cleaned or tightened then that's great! I'm hoping for the best for you on this. Anyhow, I'm not sure how familiar you are with these shields, but they're low voltage--you should be safe. I've never been shocked by these before. Of course, I am careful to almost always use gloves when I work, even cheap medical gloves are enough for this. I will however caution against one other thing: wearing rings or jewelry. They can short and ruin a board in an instant. I HAVE done that much.

I forgot to tell you this in the previous post: Some of the bezels aren't quality metal. Some are plastic (tough to fix in that case) or are some kind of weak alloy. You will only get to bend those retention tabs so many times before they snap. Take care to test the re-alignment and pressure as much as possible prior to folding the tabs and closing it all up. Sometimes it only takes a moment or two, but one display took me 25 minutes to rework. Luckily its frame was quality metal and it was able to take the abuse. Just keep these things in mind if you can.

If you manage a miracle and somehow get it fixed, do yourself a favor and glue it with 2-part clear epoxy along the edge where the metal meets the pcb. Try not to get any on the exposed surfaces of the soft conductors, if exposed. Don't go out and spend a fortune on attempting to fix a cheap lcd display, but it may be wise to try to keep glue on hand as that has saved me time and time again on mail-order widgets and electronic boards.

I wouldn't be so quick to declare the LCD as broken.

The connections may be "obvious" but from the photo, I can't tell how the LCD is wired up to the Arduino pins. Also, since the code was not provided, I can't tell which pins were being used in the LCD constructor.

I'm wondering if the wires are mis connected, shorted, or broken, and the initialization ends up sending shift commands instead Function set and Entry mode set commands.

There are about 7-8 command that get sent during 4 bit initialization. I wonder if that could cause shifts to create what we are seeing?

I would go carefully check all the wiring and make sure that nothing has moved, broken, or come loose.

--- bill

I agree Bill 100%. My info is intended to be used only when all other options have been exhausted.

I don't see how you could come up with that display as a result of improper initialization or improper commands due to wiring or program errors. I don't see how 'shifts' would cause that display either.

I think you could achieve that display by sending the specific data to the LCD to print eight spaces (0x00) followed by eight blocks (0xFF) to each row (or successively to all of the memory locations) but that most likely didn't happen here.

Since the problem arose after a working display was physically moved I still think it is a contact problem between the pc board and the display itself.

Don

Hi again, Andoni here with the same problem this time in another LCD (this one is not from DX, the teacher gave it me after burning 2 , he has used them in a lot of different projects and they work well).

First of all i want to say thank you to everybody who has wasted time in helping, this is my fist DIY proyect, so I'm not any expert but i like this world. I'm doing as final project a Greenhause controlled by arduino (duemilanove), I bought different sensors like DHT22 (temperature and humidity, digital), ambient light sensor, Soil moisture sensor, pH sensor...I need the LCD because I want to make manual and automatic control, and with the help of some Informatic friends control through Internet also.

About your posts, MAS3 I don't put the shield over the arduino because I change the inputs every day as well as i improve the different parts of the proyect. I put screws in the holes of the green PCB because space problems. After having some problems with sensors (concretly the DHT22 measures always 1% humidity....... ) , i decide to make a simulated inputs board to analyze better the program under different conditions. After burning the second LCD I replace it for a better one but without buttons, so i get the schematic and build a new one as you can see in the photo.

Floresta I'm not really sure but i know that the 3 different LCD i used before worked properly until they crash, so i think the connections and the initialization or commands are OK. Mlowther be sure that when i have time i'll try to open and clean them carefully... ;)

I'm seriously thinking now about the power supply. I use a variable one from 0-25V that we made in class after buying the components. It is in the second photo. Every time i connect it to my board I ensure with a polymeter that the voltage is 5V. It has got two control, and with the most sensitive is easy to put it in 5.00V. I analyzed the signal with the teacher and he told me it is really strong and reliable. But what about the starting peak??do you know if it could be enought to burn 3 of them?? I don't make any measurements of this magnitude.

Thanks in advanced. I'll be waiting your answers.

Andoni

i have some problems with the photos.....i think they are too big!

I take smaller photos…

  1. The new LCD burned.
  2. Power supply
  3. Button + simulated inputs

Hi again, Andoni here with the same problem this time in another LCD

This is not the same problem as in the original post.

These photographs show an LCD that is functioning correctly but is improperly initialized.

This is a result of a problem with the connections with the programming or with both.

Your contrast appears to be set properly.

Since all of your wires are the same color it is hard to do much troubleshooting of the connections using the photographs. I don't see any connection to pin 5 of the LCD so please verify that this pin is connected to GND. It also looks like you may be using the wrong data pins on your LCD. You should be using LCD pins 11, 12, 13, and 14.

Are you sure that your constructor (

LiquidCrystal lcd(RS, E, D4, D5, D6, D7);

) matches your actual connections?

Don

What do you want to say Floresta with "LCD that is functioning correctly but is improperly initialized"?

I don't know if it is improperly initialized, but it worked well before the crash happened. and now it isn't well working. I have seen the screen with so different characters (only in the first line, characters only in the right part, only in the right part but not like the first photo, where the characters are equals, I have seen characters with only one or two points width, but always with any letter oder unreadable character, only dark squares). how can i initialize it properly? by sending the specific data to the LCD to print eight spaces (0x00) followed by eight blocks (0xFF) to each row (or successively to all of the memory locations) ?

The connections of the LCD are: 1- GND 2- Power supply 5 V. 3- Contrast adjust (20K between LCDs 1 and 2) 4- RS to arduino pin 8 5- R/W to GND 6- E to arduino pin 9 11,12,13,14- DB4-7 to arduino pin 4-7 15,16 not connected (teacher told me not necesary, less power needed)

my constructor: LiquidCrystal lcd(8, 9, 4, 5, 6, 7); as you well said.

Antxoni