User manual

Appendix B: User Service
B–2
WFM 90 & WFM 91 User Manual
Display Screen
The protective screen over the LCD display is susceptible to
smudging from dirt and grease. It can be cleaned by spraying a
glass-type cleaner onto a lint-free cloth and gently rubbing the
display. Only dampen the cloth to prevent moisture from getting
behind the protective screen of the display.
Interior
Interior cleaning and maintenance should be performed by qualified
service personnel only. Instructions for interior maintenance are
provided in the service manual.
LCD Display
The LCD display will retain an image if the instrument is left on in
one display mode for an extended period of time. This is typical for
the LCD display device. The retained image will fade over time, and
that time can be accelerated by leaving the instrument turned off.
CAUTION. LCD Display Image Retention
To prevent image retention in the LCD display, enable the backlight
time-out mode or turn the instrument off if the monitor is going to be
left alone for more than two hours.