HP 8562E, Руководство по обслуживанию

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7. If the peak detector appears latched up, check LPOS-RST (U422 pin 4) for a negative
TTL level reset pulses. The reset pulses should occur every 130 and should be
approximately 250 ns wide.
8. If the reset pulses are absent, troubleshoot the Peak Detector Reset circuitry.
9. If the reset pulses are present, check the gate of Q207. The pulses should be positive-going
from -12.7 V to -1.35 V.
10. The peak detector can be made into a unity gain amplifier by shorting the, cathode of
CR203 to the anode of CR204. If the peak detector functions normally as a unity gain
amplifier, suspect Q208 or CR203 or CR204.
Refer to function block R of A3 Interface Assembly Schematic Diagram in the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
1. Press on the spectrum analyzer and set the controls as follows:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sweep time
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Detector mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . POS PEAK
2. Check that HHOLD pin 11) has 18
wide pulses every 128
3. Check that HODD pin 5) is a square wave with a period of 16.7 ms
(2 x sweep
4. Check LPOS-RST (U422 pin 4) for 200 ns low-going pulses every 128
5. Check LNEG-RST pin 12) for 200 ns low-going pulses every 128
6. Set the detector mode to NORMAL and check that LNEG-RST pin 12) has two
pulses spaced 40 apart and then a single pulse approximately 88 from the second
pulse.
7. Check HMUX-SELO pin 3) and
pin 9) according to
Table 8-8.
Table 8-8. versus Detector Mode
Detector Mode
pin 3) pin 9)
NORMAL 15
pulse every 128 40
pulse every
128
SAMPLE H
H
POS PEAK
H L
NEG PEAK
L H
8-20 Section