HP 8560A, Service Manual

Page: 337 / 450

a 0 0 0 . 0 0 v
1 0 . 0 0 . 0 0 0 s
T P 2
1
S K 1 9 7
Figure 9-8. Normal X/Y Line Generator Waveforms
Intensity
1.
2.
3.
4.
5.
The length of the vector being drawn can effect intensity and
Refer to “Long Lines Dimmer Than Short Lines” in this chapter.
Short pin 2 to pin 7. If the display does not brighten, troubleshoot LBRIGHT
switch, This switch intensifies trace A and active softkeys.
Short pin 2 to pin 3. If the display does not darken, troubleshoot switch,
This switch is used in analog zero-span.
Change the intensity (under [DISPLAY)). If the intensity does not change, troubleshoot the
intensity DAC,
is controlled from the front panel.) The amplitude of
the waveform at pin 1 should increase or decrease with intensity changes.
Clamp limits the voltage to about 4.2 V. Short to ground and set the
intensity DAC to a number greater than 80. A major portion of the waveform should be
limited to 4.2 V.
6. Troubleshoot the maximum brightness clamp,
Bad Characters or Graticule
If the displayed characters are bad but the graticule is correct (or if the symptoms are
reversed), troubleshoot the X- and Y- generator switches
and Check that
the switch driver signal LCHAR is working properly. Refer to “Display Jumbled or Trace Off
Screen” in this chapter.
9-10 Controller Section