Adjustment Procedures
TDS 500B, 600B and TDS 700A Service Manual
5–25
H Locate 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.
H Observe the luminance patches using a 6X magnifier.
H Adjust 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.
4. Adjust the display contrast:
a. Display the White Field test pattern:
H Press the center main-menu button to display the main menu.
H Press the main-menu button Tests.
H Repeatedly press the side-menu button –more– until White Field
appears in the side menu. Push White Field.
H Press the main-menu button EXECUTE; then press the side-menu
button Ok Confirm Run Test.
b. Make the contrast adjustment:
H Locate R404. It is one of the adjustments on the left side of the
instrument located just ahead of the fan. It is the fifth adjustment
from the fan.
H Monitor the luminance at center screen using a J16 photometer and a
luminance probe.
H Adjust R404 (CONTRAST) for a reading of 36 foot lamberts for
640–0077–XX display assemblies where –XX equals –06 or above.
Use a reading of 40 foot lamberts for 640–0077–XX assemblies
where –XX equals –05 or below.
NOTE. The adjustments for contrast and brightness interact with each other.
5. Restore the oscilloscope to normal operation:
a. Restore the dip switch to the settings that follow:
Switch No. 1 2 3 4 5 6 7 8
Open X
Closed X X X X X X X
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