Maintenance
1705A Spectrum Monitor
6- 17
Connect the oscilloscope probe to the anode of CR5 and the probe ground to
TP1. The signal should be a clipped sine wave of +75 to +200 V p-p.
High Voltage Oscillator Check
Connect the oscilloscope probe to T1 pin 3 (Q6 collector) and the probe ground
to TP1. Power up the supply. The signal should be a +60 V p-p, 22 kHz sine
wave.
Check the following voltages using the digital multimeter:
Table 6- 6: High Voltage Oscillator Test Points
Circuit Location
Voltage
T1, pin 4
Approxi40 V.
T1, pin 13
Less than +2 V.
U2, pin 2
Approxi4.8 V.
U2, pin 6
+4 to +11 V.
CR9, cathode
Approxi100 V.
CRT Voltage Check
NOTE
. This check requires a high voltage probe having an input resistance of 1
G
Ω
or more.
Connect the high voltage probe ground to TP1.
Load the Low Volts Supply with the instrument, or with a 20
Ω
, 2 watt resistor
loading the 5 V supply.
Power up the Power Supply.
Use the high voltage probe to measure the voltage at the anode of CR4. It
should be approximately --2530 V.
Measure the voltage at the anode end of CR3. It should be 50--150 V more
negative than the reading from the anode of CR4.
Summary of Contents for 1705A
Page 13: ...Service Safety Summary xii 1705A Spectrum Monitor ...
Page 17: ...Preface xvi 1705A Spectrum Monitor ...
Page 18: ...Introduction ...
Page 19: ......
Page 38: ...Operating Instructions ...
Page 39: ......
Page 61: ......
Page 62: ...Installation ...
Page 63: ......
Page 72: ...Theory of Operation ...
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Page 93: ...Theory of Operation 4 20 1705A Spectrum Monitor ...
Page 94: ...Checks and Adjustments ...
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Page 123: ...Checks and Adjustments 5 28 1705A Spectrum Monitor ...
Page 124: ...Maintenance ...
Page 154: ...Options ...
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Page 158: ...Replaceable Electrical Parts ...
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Page 189: ...Replaceable Electrical Parts 8 30 1705A Spectrum Monitor ...
Page 190: ...Diagrams Circuit Board Illustrations ...
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Page 214: ...Replaceable Mechanical Parts ...
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