Adjustment Procedures
5–22 TDS 684A, TDS 744A, & TDS 784A Service Manual
3. Adjust the display brightness
HLocate R403 (BRIGHTNESS). It is one of the adjustments on the
left side of the instrument located just ahead of the fan. It is the
fourth adjustment from the fan.
HObserve the luminance patches using a 6X magnifier.
HAdjust R403 (BRIGHTNESS) until the background raster lines in
the 5% luminance patch (see Figure 5–11) just disappear, while the
lines in the 10% luminance patch are just visible, when both are
viewed through the magnifier.
10% Patch
5% Patch
Figure 5–11: Five and Ten Percent Luminance Patches
4. Adjust the display contrast:
a. Display the White Field test pattern:
HPress the center main-menu button to display the main-menu.
HPress the main-menu button Tests.
HRepeatedly press the side-menu button –more– until White Field
appears in the side menu. Push White Field.