Chuckwalla Limited purchased a computer for $7,000 on January 1, 2017. Straight-line depreciation is used for the computer, based on a five-year life and a $1,000 residual value. In 2019, the estimates are revised. Chuckwalla now expects the computer will be used until December 31, 2020, when it can be sold for $500. Calculate the 2019 depreciation expense.