Specifications include, but are not limited to: 1.Duplicate any user reported problems or issues with the unit before any work is performed. 2.Retrieve onboard data from all multi probes, if any. 3.Save the onboard set up in the coefficients for future use if needed. 4.Complete visual inspection for: cracks, corrosion, missing or loose parts, pitted services, battery acid damage, other physical damage. 5.If no physical damage is present, subject the unit to a light vibration test to simulate field use. 6.Evaluate sensor performance. All sensors will be cleaned, maintained [replace DO solution and membrane when equipped, pH reference solution (if equipped), junction (if equipped)]. Test at room temperature for response time stability accuracy.