For optimum Dobson spectrophotometer performance during calibrations and observations
it is imperative that the instrument electro-mechanical system be in proper adjustment. For
spectrophotometers equipped with original (R. & J. Beck, Ltd.) electronics, a number of
maintenance suggestions are provided by Dobson (1957a). In recent years, several new electromechanical
systems have been devised for the Dobson instrument as improved replacements for
the original vacuum tube circuitry and mechanical rectifier (Else et al., 1968; Olafson, 1968;
Komhyr and Grass, 1972). Unique trouble-shooting procedures apply to each of these systems.
Observers using spectrophotometers equipped with the new electro-mechanical systems should
consult relevant documentation when repairing instruments. The 1972 Komhyr and Grass
electronics were updated with more modern components in 1999.