High/Low Band Transition Adjustment - Agilent Technologies 8753ES Option 011 Service Manual

High/Low Band Transition Adjustment

This adjustment centers the VCO (voltage controlled oscillator) of the A12 reference
assembly for high and low band operations.
Analyzer warmup time: 30 minutes.
Required Equipment and Tools
Description
Non-metallic adjustment tool
Antistatic wrist strap
Antistatic wrist strap cord
Static-control table mat and earth ground wire
Procedure
1. Press
Preset System
Stop 21 M/µ
2. Press
S PARAMETERS ANALOG IN Aux Input
Meas
REAL
Display
the next measurement.
3. Press
S PARAMETERS ANALOG IN Aux Input
Meas
.
M/µ
4. Press
Scale Ref
• If the left half of trace = 0 ± 1000 mV and right half of trace = 100 to 200 mV higher
(one to two divisions, see
• If adjustment is necessary, follow these steps:
a. Remove the upper-rear bumpers and top cover, using a torx screwdriver.
b. Adjust the VCO tune (see
0 ±125 mV. The variable capacitor, C85, has a half-turn tuning range if the A12
Reference Board is part number 08753-60209, and seven turns if the part number
is 08753-60357. Be careful not to overtighten and damage the seven-turn
capacitor.
c. Adjust the HBLB (see
175 mV (about 1 to 1.5 divisions) higher than the left half.
• Refer to Chapter 7 , "Source Troubleshooting,"
Chapter 3
SERVICE MENU
to observe part of both the low and high bands on the analog bus.
DATA→MEM DATA−MEMORY
and observe the VCO tuning trace:
.1 x1
Figure 3-20): no adjustment is necessary.
Figure
Figure 3-21) to position the right half of the trace 125 to
High/Low Band Transition Adjustment
HP/Agilent Part or Model Number
8830-0024
9300-1367
9300-0980
9300-0797
ANALOG BUS ON
22
to subtract the ground voltage from
23
3-21) to position the left half of the trace to
if you cannot perform the adjustment.
Adjustments and Correction Constants
Start 11 M/µ
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x1 Format
x1 Marker 11
3-45