HP 8562E, Service Manual

Page: 364 / 482

4 . 0 0 2 . 5 0 V 2 . 0 u s / d i v 9 6 . 0 0 u s
I I I I I I I
B L A N K I N G
nr II II II
Figure Expanded Blanking Waveforms
S K 1 9 3
Refer to function blocks D and I of A2 controller schematic diagram (sheet 1 of 4) in the
HP 8560 E-Series Spectrum
Analyzer
Component Level Information.
The two line generators are identical circuits, so the following steps apply to both. The X
generator is referenced below, with Y generator references in parentheses.
1. The voltage at pin 7 should measure 10.0 V.
2. Perform steps 1 through 5 of “Line Generators” in this chapter. If the X POS and Y POS
waveforms look different from those illustrated in Figure 10-2, check the waveforms at the
low-pass filter input (function block E in the component-level information binder).
3. The waveform at the low-pass filter should look like X POS in Figure but have an
amplitude from 0 V to V.
4. If the waveform in step 3 is incorrect, set an oscilloscope to the following settings:
Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Triggering
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External
5. Trigger the oscilloscope on the signal at pin 8 (LBRIGHT).
6. Compare the line-generator input signals at the following test points with those illustrated
in Figure 10-5. INTEGRATE and SAMPLE waveforms are replicas of VECTOR except
for polarity and amplitude. LCHAR is low when characters are drawn.
INTEGRATE: collector
SAMPLE:
collector
LCHAR: pin 9
VECTOR:
U213 Pin 9
Controller Section