Troubleshooting Using Internal Test; Power On Self Test; Pll Unlock; To Execute The Internal Test - Agilent Technologies E4991A Service Manual

Troubleshooting

Troubleshooting Using Internal Test

Troubleshooting Using Internal Test

Power On Self Test

The E4991A performs the power on self test once after the E4991A is turned on. When the
failure part is detected in the E4991A, a message of the "Power on test failed" is displayed.
The content of the power on self test is same as the internal test.

PLL unlock

When phase lock loop doesn't work in the E4991A, not "Power on test failed" but "PLL
unlock" is displayed.
• If you use the external reference signal (Opt.1D5), check to see if it is correct. If you
use the correct signal or you don't use it, there is a possibility to need repair and/or
adjustment.
• When the E4991A is turned on from cold, "PLL unlock" is displayed during few time
very occasionally because warm-up time is not enough. If "PLL unlock" is displayed
continuously after warm-up, there is a possibility to need repair and/or adjustment.
There is a possibility that A1 Reference OSC or A3 Source or A5 10MHz
Oven(Opt.1D5) gives problem.

To Execute the Internal Test

If the "Power on test failed" is displayed after the E4991A is turned on, you should
perform the internal test to isolate the faulty assembly. You can execute the internal test by
the following procedure.
Step 1. Press on the front panel.
[Menu]
Step 2. Select System Menu using
Step 3. Select
Diagnostic
Step 4. Select

Internal Test

Step 5. Select
Test Start
Internal Test
The internal test contains the following two tests.
• Analog Test
This is the test to check the function related to the analog section. When the analog test
fails, "Analog Test: FAIL" will be displayed.
• System Test
This is the test to check the function related to the digital section. When the system test
fails, "System Test: FAIL" will be displayed.
172
key.
using key and press
using key and press
using key and press
key.
key.
key in the internal test menu.
Chapter 4