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processed, cleaned, dried and stabilized?

posted Oct 19, 2014, 9:51 AM by Steve Watson   [ updated Oct 19, 2014, 9:51 AM ]
On a LinkedIn post showing the device cage from WDD001, a contact asked "What do you mean by 'processed, cleaned, dried and stabilized'? What methods will you be using for each? "

My response to his question is:

Processed
Lab intake including CoC, documenting the device, photographs, dis-assembly to capture the serial number, model, IMEI and any SD cards or SIM cards. These are the kinds of tasks any lab would be doing when a new device shows up needing acquisition.

Cleaned
Removing soil, sediment, salt or chemical build up from the PCB and connectors. On project WDD003, I will compare the recommended cleaning methods (dependent on which liquid the device has been exposed to) to understands which performs best. The tested cleaning methods will include de-ionized water, isopropyl alcohol, detergents, solvents, pastes, etc. The industry published information on cleaning devices is diverse and sometimes contradictory.

Dried
After cleaning, device PCBs will be dried using one of the three methods identified in industry BKMs - desiccants, compressed air, and a PCB oven. Project WDD005 will compare these three methods to identify which is most effective in removing moisture. For projects WDD001 and WDD002, I will be employing one or more of these methods to achieve the results of each respective project.

Stabilized
Based on what liquid a device was exposed to, I hypothesise that specific techniques and chemicals may needed to minimize the rust and reverse corrosion on PCB traces and connections. An example of this could be the application of pH neutral solvents and pates to stabilize the corrosion progress of the board. In my opinion, this is of particular importance for devices which may be part of a long-term investigation or matter where devices may need to be accessible to other parties for periods of time 6-12 months beyond initial device treatment and acquisition.
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