Wednesday, June 11, 2008

Saving Flooded Electrical and Electronic Equipment

The recent flooding in many areas of the United States reminded me that I wanted to address this issue.

I lived in South Louisiana, an area very prone to flooding, for most of my life. I worked in the electronic systems business there for more than thirty years. Spending time on the water is a big part of life in Louisiana. As a result, I have seen several thousand pieces of equipment that have flooded.

I also have seen, and heard, many very bad recommendations for drying equipment out. I can say, without hesitation, any suggestion that involves heating the unit to dry it out, without disassembling and rinsing, is a very bad idea. Putting the unit in an oven, clothes dryer, under heat lamps, in front of a hair dryer, and so on, is not the proper way to save expensive electronic or electrical equipment. None of these methods address the fact that most water has chemicals and minerals that are conductive and/or corrosive. If not properly removed they will cause damage.

Before considering having a flooded item repaired by any shop, ask how they will handle the job of initial drying. A shop that is planning on using any method of heating, prior to disassembly and cleaning, should not be given the job. Do not consider any shop that is not going to flush the unit with clean water while taking it apart. These are important questions to ask, I have seen very expensive equipment, taken to otherwise excellent repair shops, destroyed by improper drying techniques.

Some equipment will not be cost effective to save. Some equipment will not be able to be saved. But, I have found that many items can be saved if handled properly and promptly.

What should be done to improve the chances of saving equipment?

As soon as the item is removed from the water:
  • Take out any batteries that are accessible.
  • Do not let it dry out, even a little bit, if you can help it.
  • Flush with plenty of clean water.
  • Put the item in a container of clean water keeping the item completely submerged. If clean water is not available, use the water that the item was in until clean water is available.
  • Start the recovery process as fast as possible.

Just those steps will improve the chances of saving the equipment.

If you are going to try to dry the items out.

This is the method that I have used to dry out items ranging from pagers and cell phones to laptops and marine electronics.

Note: See the section below for special notes about battery packs and hard drives.

Plan to work at a sink or in a location where the unit can be flushed with clean warm water while it is being taken apart.

Gather these items prior to taking the unit out of the container of water:
  • Clean warm water supply and, if possible, distilled water for final rinse.
  • Proper tools to disassemble unit.
  • Good quality contact cleaner.
  • Soap, I use Dawn Ultra. Mix this ahead of time, 1 tablespoon to 1 gallon warm water.
  • Light machine oil.
  • WD-40.
  • Silicon spray.
  • Hair dryer.
  • Dry compressed air.
  • Soft nylon brushes.
  • Brass brush.
  • Plenty of soft towels and rags.
  • Static controlled work station.

Once you have everything ready:

Work fast! Disassemble the item as much as you can. Items that can not be cleaned within a few minutes should be placed back in a container of fresh water.

Rinse each piece with clean warm water then look for any deposits. Pay close attention to areas that could trap minerals, like the area between an IC and circuit board. These should be cleaned with a soft nylon brush dipped in the soap. Follow with another rinse to get all traces of soap off. Run clean water into any controls and switches. Use distilled water for final rinse.

Place each item on a soft towel and begin drying as you finish rinsing. Pat dry all parts that you can get to. Then use dry compressed air to blow out any water that you could not get by hand. Use a hair dryer on low heat to be sure all traces of water are dried out.

Spray controls, switches and connectors with WD-40 and follow with contact cleaner. Be sure that the contact cleaner is compatible with any plastic parts before using it.

Metal parts should be wiped then examined for corrosion. If light rust is found, use the brass brush to remove it. Follow up, if the part is not stainless or aluminum, by wiping with a soft cloth and a light machine oil. Items, like hinges, should be sprayed with WD-40 then allowed to dry. Follow this with silicon spray.

Leave all parts, at least overnight, on dry soft towels.

Before reassembly, check for any signs of corrosion, rust, and overheating. Pay attention to circuits around the battery or power connections. Also, look closely at things like displays for any sign of moisture remaining in them.

Once reassembled, check for short circuits prior to putting power on the item. When powered up, watch closely for several hours to be sure there are no signs of overheating.

What about battery packs and hard drives?

These two items need special attention.

Battery packs should be replaced. With that said, I normally dry them out the same way as the rest of the circuits. Then I test them to see if they will still work. Most of the time, they do. However, I never give a warranty on them. If I am working on an item for a client, I always replace the batteries.

Hard drives should never be powered up except by a professional hard drive recovery facility! They must be replaced always.

If a hard drive has data that must be recovered, these are the steps that I use:

  • Remove from the equipment.
  • Rinse with clean warm water only.
  • Place in sealed container of clean water.
  • Send, overnight, to recovery facility.

Contact a recovery facility ahead of time and make sure they are equipped to handle flooded drives and experienced with them. They will tell you how to package the drive for shipping to them.


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