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Adjustment Procedures
2715 Spectrum Analyzer Service Manual
5-9
Instrument with serial number B030000 or above. Adjust R639, R669, R680,
R703, R704, R705, R900, and R930 on the Power Supply board and R6, R7, and
R110 on the rear panel.
H Test equipment required:
Voltage Variable Isolation Transformer
Test Oscilloscope with Probes
Multimeter (DMM)
High Voltage Probe (X1000)
WARNING. Use an isolation transformer when working on the Power Supply.
The transformer must have a three wire input and output connector with ground
through the input and output. Stancor GIS21000 is an example of a suitable
transformer.
Hazardous line potential exists on the Power Supply board at all times the
instrument power cord is connected. If it becomes necessary to r emove the shield
on the bottom of the Power Supply board, use extreme caution when handling the
instrument.
Refer to Figure 5--1 for the location of most adjustments and test points.
1. Connect an Isolation T ransformer in line with the Spectrum Analyzer power
input and the AC line voltage source of 90 to 250 VAC.
2. Set R669 (DTC) on the Power Supply board to midrange position.
3. Apply power to the Spectrum Analyzer and turn on the graticule lights
(DSPL 6).
4. Adjust R937 (+5 V ADJ) on the Power Supply board for +5.0 VDC at the
+5 V test point.
5. Set the test oscilloscope controls as follows:
Channel 1
Coupling AC
Deflection Factor 20 mV/div
Trigger Channel 1, positive edge
Time Base 5 s/div
6. Place the Channel 2 probe near R680 on the Power Supply board. The test
oscilloscope should display approximately four periods of the waveform at
TP250.