To Troubleshoot Tachometer Failures - Agilent Technologies 35670A Service Manual

Troubleshooting the Analyzer

To troubleshoot tachometer failures

To troubleshoot tachometer failures
Use this test to isolate tachometer failures to the A10 Rear Panel assembly or A6
Digital assembly.
Step 1. Check the rear panel tachometer input.
G
• Set the power switch to off (
• Remove the seven screws holding the rear panel to the analyzer and lean the
rear panel back until the A10 Rear panel assembly is visible. Keep the
cables connected.
• Connect the SOURCE output to the TACH input on the rear panel using a
BNC cable.
• Set the power switch to on (
• Press the following keys:
[
System Utility
[
CALIBRATN
[
AUTO CAL
[ ]
Rtn
[ ]
MORE
[
SELF TEST
[
LOOP MODE
[
FUNCTIONL TESTS
[
TACHOMETR
[
CONTINUE
• Using an oscilloscope and 1 M 10:1 probe, check the following signal.
The signal should be displayed while the self test is running. Each time the self test
restarts, the source output to the tachometer input will be interrupted.
Oscilloscope Setup
Connect CH1 to A10 TP1
CH1 V/div 1 V/div
Input Impedance
1 M Ω
CH1 Coupling
dc
Probe Atten
10
Display Mode
Real Time
Time/div
2 ms/div
Trigger
Auto
• If the signal is incorrect, the A10 Rear Panel assembly is probably faulty.
4-70
).
O
).
l
]
]
OFF ]
]
ON ]
]
]
]
Parameters
Amplitude
Time
Duty Cycle
Pulse shape
Agilent 35670A
Waveform