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2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
120
A19 Diagnostic Tree
(A/M Subsection 9)
This subsection describes the diagnostic tree for the A19 module and
associated circuits on A6. The A19 module is an ovenized voltage-controlled,
quartz-crystal oscillator (VCXO), it receives oven and oscillator power from
the A6 module. At power-up, the VCXO requires a warm-up time of at least
10 minutes before its output is stable.
The 10 MHz VCXO output is tuned over a nominal range of
±
3 Hz by an
electronic frequency control (EFC) voltage. The EFC signal is generated by a
DAC on A6.
3.9.1.1 A6 Unloaded A19-Power-Supply Voltages
1
Power down the instrument and remove A6.
2
Check the continuity of fuses A6- F3, F4, F5, (2.5
Ω
or less) and replace as
required.
3
Mount A6 in the instrument with the short extender card
(05071-60051).
4
Disconnect A19 from A1 at A1J11 and CBT cable from A2J2.
5
Disconnect the semi-rigid cable from A19 to A9J5.
6
Connect the signal generator output (set to provide 10 MHz at
+7 dBm) to A9J5.
7
Apply power to the instrument. (Wait until LCD displays
Fatal Error
.)
8
Measure A19 supply voltages with a DMM at test points TP9, TP8 and TP7
on A6. Voltages should be as follows:
TP9, (+12 V nominal), more than 11.75 and less than 12.75 volts.
TP8, (-12 V nominal), more than -12.75 and less than -11.75 volts.
TP7, (+10.8 V nominal), more than 10.3 and less than 11.3 volts.
QUESTION:
Are the power supply voltages correct?
If Yes:
Go to, 3.9.1.2.
If No:
Remove power, replace A6, and retest.
Содержание 5071A
Страница 2: ......
Страница 40: ...1 Performance Tests Verifying Specifications 5071A Complete Performance Tests 24 ...
Страница 48: ...2 Service Pre Troubleshooting Information 32 Figure 2 1 Instrument Top View ...
Страница 147: ...3 Theory of Operation Functional Block Descriptions 131 Figure 3 2 5071A Overall Block Diagram ...
Страница 148: ...3 Theory of Operation Functional Block Descriptions 132 Figure 3 2 5071A Overall Block Diagram Continued ...
Страница 164: ...3 Theory of Operation Functional Block Descriptions 148 Figure 3 3 A1 Power Supply Distribution Schematic Diagram ...
Страница 166: ...3 Theory of Operation Functional Block Descriptions 150 Figure 3 4 A1 Slot Module Interconnect Diagram ...
Страница 168: ...3 Theory of Operation Functional Block Descriptions 152 Figure 3 5 Power Supply Block Diagram ...
Страница 171: ...3 Theory of Operation Functional Block Descriptions 155 Figure 3 7 Opt 048 A1 Slot Module Interconnect Diagram ...
Страница 172: ...3 Theory of Operation Functional Block Descriptions 156 Figure 3 8 Opt 048 Power Supply Block Diagram ...
Страница 173: ......
Страница 175: ...3 Theory of Operation Functional Block Descriptions 159 Figure 3 9 A1 Component Locator Diagram ...
Страница 194: ...5 Replaceable Parts How To Order A Part 178 ...
Страница 197: ......