Repair a Malfunctioning LCD


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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.

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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.

Step 2: Disassembly

Disassemble the device to expose the LCD. Obviously, this step will vary by device. If you are having trouble getting your particular device apart, try Googleing "'yourdevicename' disassembly".

Step 3: Prep the Screen

Prepare the screen for repair by exposing the ribbon cable on the backside of the screen. In this phone, there is a plastic clip holding the LCD that must be temporarily removed. A plastic-coated paper clip is a handy for holding the LCD down while you work.

Step 4: Repair the Connections

Using LOW heat (you do not want to melt the ribbon or the solder on the board), slowly heat the ribbon cable where it is connected to the mainboard to soften the glue. At the same time, gently but firmly rub the connection strip with the pencil eraser.
Tips:
1. Try to avoid directing too much hot air onto the LCD itself as this could damage it.
2. Apply enough heat to melt the glue holding the ribbon connection, but not enough to melt the cable itself.
3. If after the first try the problem is not resolved, try rubbing the connections down with something firmer. I repaired two identical phones using this method, and the second one required that I use the back of a plastic screwdriver to force down the connections.

Step 5: Results

With any luck, your results will be something like this. This repair, including disassembly, took approximately ten minutes to complete and the results are excellent; the screen is 100% functional again.

12 People Made This Project!

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164 Discussions

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coco.dozo

Question 3 months ago on Step 2

Google offers no link as to how to open an AEG Voxtel D235 handset. After opening the battery compartment and removing batteries and the two Philips screws at the bottom, the upper half refuses to budge. Is there a method for opening the upper part, to access the LCD screen connector for repair? Any suggestions appreciated.

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canterburyflyer

10 months ago

I brought a DYMO Label Maker back to life. The most difficult thing was disassembly.
I Used a Hot AIr Rework device set at 250 Centigrade.
Nozzle about 2cm from the ribbon and as I heated I used the end of a paint brush carefully to massage the connection.
Before I thought that anything had been acheived I tested and found all characters were visable.
I must say thanks to you for giving me the impetus, courage,..huevos to attempt this.

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xoundbox

2 years ago

Fixed my old calculator! Just wanted to say thank you!

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IrishSnow35

3 years ago

This made me squeal when it worked! I fixed an old treadmill computer from a machine I bought second-hand. There was a broken connection on the breadboard so I dunno if that work but we'll see! I didn't have a heat gun, blow dryer or clothes iron to use, but I made it work with the end of my hot glue gun. Thanks, God bless!

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andy364earn101

Reply 4 years ago on Introduction

No ribbon strip on my CMS921 just 8 pins that plug into the PCB. Please advise!! :-)

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JamesI6andy364

Reply 4 years ago

I just got my CM921 to work - so, carefully unplug or remove the lcd unit from the circuit board (8 pins i think) then separate the white board (same size as the lcd) from the back of the lcd display (it was glued on one side and i used a scalpel) the lcd will then flip over and you can see the ribbon, then follow the instructions above, return the lcd back down on top of the little white board as before and plug it back in...

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MattM353JamesI6

Reply 2 years ago

Thanks for your post. You just saved me a £25 repair cost and a 1 week wait! Easy-peasey, broken to working in 10 minutes.

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ET60andy364

Reply 3 years ago

There may be a thin conductive rubber strip between the glass of the display & the board it is attached to. Over time this rubber can leak an insulating compound onto the interface connection that can, at times, be removed by removing the strip and gently rubbing it with a clean soft eraser. Be gentle as it can be fragile & easily damaged. This was an effective repair in the early days of these displays.

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rorro33

2 years ago

I did it ! and My old house phone is working again!Thank you so much!!!!

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Salils

4 years ago on Introduction

Has anyone done this with a TI-83+ graphing calculator or similar? I'm not sure which cable/part of the cable is likely not making contact? I'm missing a row of pixels. Any thoughts?

FullSizeRender-8-2.jpgFullSizeRender-9-3.jpgFullSizeRender-10-2.jpg
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JeanU2Salils

Reply 3 years ago

Fix the cable just below J6, J4, & CON2 (you should be able to lift the LCD screen up off the board & pull the ribbon semi-straight to see the connections). There is a YouTube video with exact instructions for the TI-83+.

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SalilsSalils

Reply 4 years ago on Introduction

ps: I've tried a couple places but I'm not sure where is most likely and I'm afraid to be too aggressive with the heat gun until I'm certain.

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Painter VerLan

3 years ago

Anyone tried to repair Sharp Oxford dictionary PW E550? The ribbon cable is held down by a piece of tape. Before I run out to buy a hot air gun would it work on tape?

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KristyS20Painter VerLan

Reply 3 years ago

I just repaired a calculator that had the connectors held down by tape. I used a hairdryer on high heat and it did not mess up the tape.

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KristyS20

3 years ago

Thank you!!! This totally worked. I just repaired my TI-36X Solar Calculator that had 2 semi-burnt out cells.

I used a hair dryer on the highest setting and the handle of a plastic makeup brush to rub the connectors as I heated them up. It did take about 5 minutes or so to get the right amount of heat and to find the exact contacts that were broken.

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loulos1

3 years ago

Thank you it work nicely

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radiumfu

4 years ago on Introduction

Very helpful, I fixed my kill a watts P4480, will try fix my 2001 Audi A4 dashboard center LCD display panel.