Hitachi L-2100 Instruction Manual page 15

(f) Free from an amount of dust and dirt.
Contamination with dust and dirt could deteriorate the
performance of the instrument.
(g) No abrupt fluctuations in power voltage.
Fluctuations in power voltage could cause noise in
analytical data.
(h) Do not connect the instrument to a power line used by
an electric device that is not equipped with a noise
suppressor circuit (e.g., stirrer, vibrator).
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