LCD Problems

 

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After a phone gets wet, the most common problem is usually with the LCD display. The LCD may not function at all, or may function intermittently, or may even turn solid white or blue, not producing any images.

Other common problems include the screen turning off randomly, or even a distorted screen where parts of the image are missing, upside down or even mirrored (especially common with LG phones).

 

So what can you do to fix a phone with this problem?

The first thing to do is immediately pull the battery out and let the phone dry (under a warm light- or on your car's dashboard its hot outside). Once the phone is dried out, it needs to be serviced to remove the oxidation that formed between the circuits.

Lots of people skip the last step- they think that drying the phone is going to solve the problem. However, drying the phone out is only part of the solution. Its important to realize at any time your phone can overpower causing permanent damage. At that point, the entire circuit board (the "brains" of the phone) will have to be replaced. The quicker the battery is removed from the phone, the higher the chances of recovery are.

Lets take a look at what causes the most common LCD problems:

The image below is what the average phone looks like with the plastic covers removed. There are three major parts: 1. the LCD 2. the flex cable and 3. the circuit board.

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Arrow 1- The LCD is connected to the flex cable

 

 

Arrow 2- The flex cable is connected to the LCD (top end) and the circuit board (bottom end).

 

 

 

Arrow 3- The circuit board is the "brains" of the phone

 

 

 

 

 

 

The function of the flex cable is to connect and transmit data from the circuit board to the LCD module, and vice versa. Its sort of like the phones spinal chord. If you were to unplug the flex cable, you would notice about 50 tiny pins on one end (making up the plug) and roughly 30 pins on the other end (making up the other end of the plug)

As you can imagine, depending on which pin gets disrupted, depends on the function(s) that may be lost. One thing about the pins- several of them are space fillers- not connected to anything (up to 15% of them). But the ones that are used, each have a specific function.

Below shows normal connector cable plugs (which connects the circuit board to the LCD). Notice the gold pins on both ends are bright and shiny.

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Below, liquid has entered the phone, and has gotten in between the plug, where oxidation has developed. As you can see, many of the pins are shorted out.

 

1 All of the shorted out pins are going to cause a misregulation in voltage, causing problems.

 

Functions that are regulated here include the LCD (for both the inner and outer LCD's), the backlight, the inner speaker, and the vibrator.

So depending on which specific pins get wet, determines which functions may or may not work. Since the LCD requires the most pins though (at least 10 pins are involved in the LCD processing) if just one of them 10 are damaged, the LCD wont function properly.

The flex cable is susceptible to liquid damage: Since the flex cable connects both ends of the phone (the LCD at one end, the circuit board at the other end) it is most susceptible to damage because no matter which end gets wet (top or bottom) the flex cable extends to both parts, and has a good chance of getting liquid inside.

Once the liquid hits the metal pins, oxidation will start to form, and it will continue until the liquid evaporates. Oxidation causes the circuits to be misregulation or may cause the entire circuit board to short out completely.

 

For best results, immediately remove the battery from the phone then let it dry out, then have your phone serviced.