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In a world of aging circuitry and components, many companies often try to maintain electronic systems as long as possible. Most companies have developed plans to retrofit systems and update circuitry. Through-hole devices will be replaced by surface mount technology, discrete ICs will be eliminated with system on chip technology, and multiple circuit cards will be replaced with only one printed wiring assembly. Their goal is modernization and reduction in scale. But what can a company do when nature suddenly wrecks an electronic system just prior to this transition to this updated technology?

Hurricane Katrina subjected many large, and hard to replace, circuit card assemblies to severely adverse conditions. For one particular company, thousands of boards were submerged in standing water with heavy contaminants. Even though this company had plans in place to ultimately replace the aging systems, the newer units were still in the design phase at the time of the disaster, and not ready to be implemented as replacements. The company quickly decided to salvage and repair the existing systems, and it was determined that the EMPF's facilities would be ideal for the task

A process flow diagram (Figure 2-1) was developed to determine what cleaning process would be applied to a given piece of hardware, depending on the type of board and components, and the level of contamination.

The boards were unpacked from their boxes and anti-static bags and placed in trays on a multitude of racks. The bags and desiccant were discarded due to contamination. New antistatic bags were ordered that would accommodate the boards even if larger than necessary. New desiccant was also acquired to be used within each new bag. Re-packaging procedures were basically the same as if the products were new, and not salvage material.

All boards were then inspected by an electronics manufacturing technician for levels of particulate matter, process compatibility, and to assess whether or not the boards were recoverable. Additionally, the history of each board's storage and exposure conditions were evaluated, with a focus on original date of manufacture and time in storage. Severity of exposure, storage location (e.g., in crates at the floor level, shelved above the water line, etc.), and any processing or recovery operations performed after exposure to the conditions created by the storm were also examined. Figure 2-2 is an example of the condidtion of one of the boards at its initial examination.

Most small boards immediately went to Cleaning (I). These were boards that were often lightly contaminated and did not have special components. Clean DI water at 130°F in an inline aqueous cleaning system (Technical Devices NuClean PolySMT 318XL) was used with a saponifier (Kyzen Aquanox A4520).

Many boards went to a Disassembly and Component removal phase, in which all socketed components had to be removed. This is because the corrosion was severe on the leads, and to ensure that contaminants were cleaned from within the socket. All daughter boards were removed as well for the same reason. Other components were also removed and separated, including paper insulators, all ICs, all displays, and all batteries.

Boards and components that were heavily contaminated went to a Pre-wash (II) phase using Kyzen Cybersolv SB 8501 to remove particulates. Boards were soaked for several minutes, lightly brushed, and then rinsed in cleaner baths of solution. Afterwards, the boards went to Cleaning.

Boards underwent 100% visual inspection for cleanliness. Every 100th board underwent ionic cleanliness testing using Resistivity of Solvent Extract, with the requirement to have 10.06 micrograms of NaCl equivalents/square inch maximum. All boards were then baked dry at 60°C for 8 hours.

In all, more than 4,450 boards were cleaned at the EMPF and then sent to another lab for testing. Figure 2-3 shows a board after having gone through the cleaning process. The boards having been recovered in roughly half the time that was projected, the customer was able to reinstall this hardware and bring their systems back online sooner than expected.

The EMPF’s facilities were able to assist with the salvage and repair operation for the company, effectivly helping them to resume normal operations in the face of what otherwise would have been a lengthy downtime following the devastation cause by hurricane Katrina.

This is an extreme example of the kind of printed wiring assembly analysis and cleaning work that takes place at the EMPF’s facilities. To find more information on the EMPF’s projects and capabilities, or how the EMPF can help you resolve your electronics issues, visit the EMPF website at http://www.empf.org, or call the EMPF helpline at (610) 362-1320.