HP 8562E Service Manual page 362

5. Compare the signals at the following test points with those illustrated in Figure 10-2.
x POS:
Y POS:
Z OUT:
BLANKING: A2J202 pin 15
Waveforms displayed on an analog scope may show considerably more spikes.
This is normal and is due to the wider displayed bandwidth.
6. Troubleshoot the circuits associated with any bad waveforms.
x
Y POS
z
B L A N K I N G
Refer to function block J of A2 Controller Schematic Diagram (sheet 1 of 4) in the
HP 8560 E-Series
Spectrum
1. Using an oscilloscope, check for blanking pulses at A2J202 pin 15. A2U206 pin 6 should be
at a TTL high. Blanking pulses turn the CRT beam off during the sample time of the line
generators and when moving the CRT beam to a new position for drawing the next vector.
2. Set an oscilloscope to the following settings:
Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 V/div
Amplitude offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +2.5 V
Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 ps/div
Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External
3. Externally trigger the oscilloscope off the signal at A2U207 pin 8 (LBRIGHT).
0 . 0 0 v
3 . 0 0 V/div
Figure 10-2. Line Generator Output Waveforms
Component Level Information.
Analyzer
1 .00 m s / d i v 0 . 0 0 0 5
Controller Section 10-5
S K 1 9 1