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We have already outlined in a previous blog post that water / liquid damaged cell phones are beyond economic repair, if repairable at all.  In this follow up we have decided to outline WHY.  Quite simply, the proper procedure is tedious, time consuming and requires replacement of a significant number of parts.  Keep in mind, that while you may only be experiencing a minor issue (a few keys not working), there can be significant additional latent damage that will lead to additional failures over time.  And if this potential for further damage is not taken into account then it shouldn’t be difficult to realize that the phone cannot be truly repaired as any ‘fix’ likely will be only temporary, until the unforeseen damage materializes.  So, we find it unacceptable to consider a liquid damaged cell phone repaired unless it is done correctly by making sure we address not only the obvious but the not-so-obvious damage as well.  To simply ‘fix’ the issue at hand will result in your spending money on a non guaranteed ‘repair’ with a high probability of future failures.  And repair shops that offer or claim to be able repair liquid damaged phones very obviously lack the knowledge and/or don’t understand why the repairs are not economically feasible.  So, let’s examine the process in some detail.

The first step is up to the user: The battery should be removed IMMEDIATELY.  This will minimize the chance for further shorts by removing the primary electrical source.  (It will not eliminate the threat of damage since there will be an internal battery and stored electrical capacity within the circuitry of the phone.)  Users are smart to rely on internet advice about removing the phone’s battery.  However, there are way too many pointless suggestions offered on the internet about how to deal with wet phones, such as heating the phone with a hair dryer to dry it or “Old Wives”  tale  remedies like using rice to absorb the moisture.  It is important for the owner of a water/liquid damaged cell phone to realize that no ‘internet remedy’ will address the core issue of electrical damage to the phone.   The best advice to follow when you have a water/liquid damaged phone is to get it to a qualified repair shop as soon as possible.

Once a damaged cell phone arrives at the shop it needs to be completely disassembled.  The main PCB needs to be inspected for any visible, catastrophic damage such as de-lamination of the PCB layers or burnt areas.  Any damage of this sort is deemed un-repairable.  Once the unit passes initial inspection, the cleaning / repair / testing procedure can begin.

• The internal battery will be removed and capacitors need to be discharged and / or removed
• Most vibe motors, speakers, cameras, microphones, shields will be removed.
• The PCB will be ultrasonically cleaned for several hours in a specialized cleaning solution.
• The PCB will be rinsed, dried and inspected.
• Any residue remaining will be hand cleaned.
• Removed components are re-installed (using new parts for electro mechanical parts – batteries, capacitors, microphones, speakers, cameras, etc to avoid latent failure and reduce the time needed to test each component individually)
• Each path / circuit (charging, audio, display, etc) on the PCB must be tested for electrical continuity.

• Breaks in continuity will need to be isolated by testing the path at  various points to isolate the damaged component.
• The affected component is replaced and the circuit re-tested.
• The procedure is repeated until all paths are verified.

Then the process is repeated for secondary PCBs.  In many cases, those secondary boards will simply be replaced.  For any clam shell or ‘flip’ phone, the flexible PCBs will also need to be replaced.

As part of the re-assembly procedure, the Liquid Crystal Displays (LCDs) will be replaced.  Most LCDs are now part of an integrated PCB that does not allow for cleaning and testing.  Since there is a high potential failure rate for LCDs once exposed to moisture, failure to replace them will compromise the repair.

When the foregoing has been completed the unit is re-assembled with a new battery.  This is important because batteries are sealed units, with high probability that they short internally once wet. Since a defective battery can damage the newly repaired cell phone it would be pointless to repair the phone and not replace a potentially damaged battery. With a new battery installed the repaired cell phone is put through a series of final tests to ensure correct operation.

Most phones that we have encountered that were exposed to moisture had NOT been submerged, instead coming in contact with a minimal amount of liquid.   This may lead one to believe that it may be possible to forgo a number of the repair steps previously noted, including replacing flex PCBs, LCDs and batteries.  However, liquid is very pervasive and its affects on electronic circuits is very damaging.  Since any portion / component of a phone that comes into contact with liquid needs to be cleaned or replaced to properly repair the cell phone,  even minimal exposure to liquid will require 2 to 3 hours to evaluate, clean and test the phone.  At shop rates of $50 to $75 per hour, very few phones are even worth repairing, fewer still once the cost for parts is added.

Consequently, based on accepting the work that should be done to properly repair a water/liquid damaged cell phone (assuming it can be repaired), it is not economically logical to perform such repairs, and it would be most prudent to be extremely skeptical of any repair shop that offers or claims to be able to do so because it just can’t be justified.

Tags: cell phone repair, water damage, white paper

This entry was posted on Wednesday, February 10th, 2010 at 9:33 pm and is filed under Cell Phone Repair, White Papers. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.