Repair a Malfunctioning LCD

This Instructable will show you how to repair a LCD that has dead rows and\or columns using a minimum of time and tools. The example shown here is a small LCD in a cordless telephone, but the same principle can be used in other devices as well.

Step 1: Tools Needed

This fix can be performed using a minimum of tools. You need only the tools necessary to disassemble the device (in this case only one screwdriver was necessary), a hot-air gun (a powerful hair dryer may work), and a pencil eraser.

Comments

[jujavie]

You are a genius. I've repaired my DECT display using a hair dryer. I scared because the screen went almost to black. It appeared a big black spot on the screen but it began to disappear as soon as the screen was cooling down. Later the screen was perfect. Thank you.

[wingerr]

Is there any reference describing the nature of the signals on the ribbon cable and interface at the LCD display? I've got an Ambient 5 day weather forecaster with missing symbols on the display, likely due to open connections on the ribbon. I'll give it a try with a hot glue gun for heating up the connections, but there may be some open traces in the ribbon itself from what I could see. Is the adhesive actually in between the conductive paths on the full length of the ribbon or was it applied only at the connection surface. Wondering if i can cut away the bad section and use a fresh section.

[Inventor_in_the_making]

Thanks for the great advice!!! I used your tip to repair the lcd screen on my Honeywell CM921 wireless thermostat, saving me £80 - £100!!

[gnrsu]

i think the software solution is safer and easier, why not try them first, i found two here: appnee.com/udpixel/

[suchasmallworld]

I don't have a hot air gun, I used a glue gun instead. I wrapped the glue gun tip with aluminum foil to prevent the glue from flowing out. Then run the glue gun back and forth over the ribbon. It is because I cannot control the temperature of the glue gun, I used the speed of running the glue gun to control the temperature. I started with a faster action and see if the ribbon is "glued" onto the PCB board. If not, then slowed the speed until I found a good speed where the ribbon started to stay on the PCB board. It worked. Thanks for the idea from blakhatt.

[chaoticandrandom]

I have just succeeded with the hot glue gun and tin foil. This method was really good for a complete re-application of the LCD plastic ribbon.

My LCD ribbon was very worn and open circuit so i removed the ribbon carefully from the PCB end and trimmed it back using a scalpel and ruler so i had a clean ribbon. You must make sure you have enough ribbon length to do this. Also clean off any old LCD ribbon debris from PCB pads.

Then to re-apply use the hot glue gun and tinfoil method but only tack down one end first of the ribbon to the PCB to get good alignment. You can check alignment with magnify glass. Then tack down the rest.

[marlarius]

I have 3 Philips cordless phones that all have broken displays in various degrees. Using your instructions I fixed them all within half an hour!

I used the hotair tip for my Portasol gas soldering iron as the heater. It is perfect for the purpose.

I captured the steps in these 4 images.

[Tilcave]

Before you start heating and rubbing the ribbon, look at it with a magnifying glass first, and see if the the ribbon contacts are aligned or unaligned with each circuit board contact. If the are unaligned with each contact already, then ONLY rub in one direction (the direction that would fix the alignments). Rubbing back AND forth with heat wasn't working for me. Then I used a magnifying glass and saw all the contacts were misaligned in to the right. This was my ah-ha moment. So while the glue was warm, I rubbed the ribbon ONLY to the left 20 times. The alignment still looked too far right to me, but the display turned out perfect so that was good enough for me.

[lepreazul]

thank you! I repaired the LCD diplay of my Dymo Labelpoint 100 with a hair dryer!

[airsnake57]

There is an old TI calculator model I really like to keep in my pocket. I have gone through a few that ended up with bad displays. I followed this link and TA DA! I was able to fix 3 out of 3!!!! I am very impressed. Thanks!

[markey1979]

It worked on my TI-86 graphing calculator, but I do not know if I would ever do that again. What a pain to gain access to the connections on the lcd.......

[paulrusu]

If you are interested in complete professional information on how to repair LCD televisions, please be sure to check out this link: http://unique.octopis.com/LCD_Repair.htm

[JellyWoo]

Will this work with something with a bigger screen? (http://www.franklin.com/estore/dictionary/SCD-1870/)

[paulrusu]

If you are interested in complete professional information on how to repair LCD televisions, please be sure to check out this link: http://unique.octopis.com/LCD_Repair.htm

[donkeytits1]

The edge of a household iron also works.

Just used it to repair my Sharp Calculator!

[suchasmallworld]

I tried to repair another phone, unfortunately I broke the connecting ribbon which is same as blakhatt's. Does anyone know where I can buy online or in Toronto, Ontario, Canada area? Thanks in advance.

[jmartin40]

I used the hex head of a small electronics screwdriver and heated the head with a candle. Obviously the head has to be very smooth. I used the edge of the hex head and ran it down the connector of my calculator. It cools fairly quickly so you have to keep reheating it. It's like using an old fashioned iron you heat in the fireplace.
I filled the screen with 8s and did a calculation to fill all of the display elements. I ran my finger nail along the connection to see which part of the ribbon affected what part of the screen so I knew where to iron each time.

[fgozulio]

i hope this works on a CANNON MP41DHII
i got a hole bunch of them and they are broken up abit, mostly buttons and all the lcd screens are busted so i wanted to fix them

[hugomerlo]

Hello, I read these steps and I was skeptical about the results. Then I read all your comments and I became thruster. I am glad I tried since I was able to repair two baby LCD monitors. One was corrected 100% and the other about 95%. I had to heat the ribbon four times in order to get these results and I just rubbed as hard as in paper trying to erase a strong mark pencil writing. It is almost as good as new. Thanks for saving my Angel Care LCD Monitors!!

[pkertt]

i tried this with a hairdryer on"hi" and it worked great!! you saved buying a new phone due to the un readable display. Thanks for a real handy instructable!!

[strange_f]

I don't know how this works, but it did work. I used a hairdryer, nail file, and screwdriver. The hardest part was getting my old Vtech 2468 apart. It had a hidden screw. It's not 100% like new but a good 95%.

I did have to heat the ribbon up three times to get the 95%. I didn't know how hot to get it or how hard to rub. Each time I would stop and then plug the battery back in to check then unplug and try again. I'm sure four times would have been the ticket.

Awesome instructable.

[azendejas]

Did not work for me... I did something wrong... I guess...

[theimaginaryduck]

Just commenting to say I tried this with my electronic dictionary -- the screen was so bad it was pretty much unusable. I read these steps and I was really sceptical, thinking, "There's no way in hell this is going to work for me," but tried it anyway because I didn't want to fork out the money to pay for a new one, if I could help it. The result? Almost as good as new! (There's just one column of pixels which appears blank... damn! But I've had that problem before and it somehow came back on its own, so with any luck it'll sort itself out...) So a million thanks to you for saving my dictionary!!

[Zaphodd]

Just used this techniqe with an 2line lcd on an HP CP1700 printer. Used the back end of a sharpie to rub down the contacts/cable - worked great!

Thanks.

[wmackintosh]

I repaired my printing calculator following your instructions. As the LCD connections are between glass plates I had to exert quite a lot of pressure with the rubber, and get the unit quite hot. After several attempts I succeeded. The liquid did overflow when hot, but it all flowed back. When the alternative is the bin, I thought I would just keep going as the heat and pressure technique is obviously correct. Thank you.

[settheraytojerry]

Thank you very much Blakhatt! I was able to repair the lcd in my cordless phone also, thanks to your useful instructable.

[Valyntyn]

 Excellent tip!  Armed with this knowledge I successfully completed a repair on my wife's 2003 Weight Watcher calculator.  

Many thanks!
Valyntyn
B.C. Canada

[sctirvn687]

Thanks for posting. Used your idea on a similar phone and It completely fixed the display. I would have got rid of the phone if not for this instructable. I just thought the display went bad.

[seabeepirate]

pretty cool. will this approach work on say a microwave LCD or maybe an alarm clock?

[Hycro]

Depending on the alarm clock...those ones with the red lines that make up the numbers are actually surface mount LEDs, made to look like an LCD.

[ramses]

yes, but since those are line powered, be extremely careful of capacitors in particular. I wouldn't mess with the microwave because there is a huge cap in there, and you could damage the magnetron/ shielding to the point where it could leak microwaves and give you cataracts and fry all unshielded electronics in the area.

[Steel_Sculptor]

maestro8 is quite correct with his reply. The sheilding within a microwave isnt as critical as the scare mongers make out. I remember talking with techs regarding microwaves when they first came out. To test, you would jam the door switch and put your hand in on low power to feel if there was any 'warming'. Obviously they werent as high in power as they are now but it was a quick test that was common practice among original m'wave techs.

[ramses]

meh. but some people take things apart with drills and hacksaws. about the cap, some go up to .9uf, storing around 1.8 joules at 2kv. while most likely not lethal, it wouldn't be pleasant.

[Furball_Fidelis]

Lol. homebrew EMP from a microwave....hmm

[he who crashes often]

been there, done that, got arrested =P

[maestro8]

To what "huge cap" are you referring? Most microwaves have a small (100s of pf) capacitor in the HV stage, but it is often coupled with a parallel resistor that would drain any charge on the cap quite quickly. Even without the resistor, the cap would drain itself in a small fraction of a second, through the resistance of the circuit in which it is connected. Also, the magnetron and shielding isn't as fragile as you're implying. It would take a hacksaw or drill to do the type of damage that would cause microwaves to leak. Even then, the leaked microwaves lose power as they dissipate into the room (remember the inverse-square law?) It would take quite a large leak to damage anything in the vicinity.

[mrsplooge]

Actually, it would only take a very small hole, the size of 1/2 wavelength or a multiple thereof to radiate and cause EMI. Hence the term, micro-wave.

[mrsplooge]

for a fun read, check out Waveguides.

[alopix]

It is really healpful!
I will try it into two philips cordless phones.

[dgclegg]

Thanks for the tip! I tried it with a hairdryer, and it worked for 75% of the rows. Perhaps the rest are not fixable by this means.