Anritsu MG3702xA Series, Maintenance Manual

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5-5 Troubleshooting Tables Chapter 5 — Troubleshooting
5-20 PN: 10370-10372 Rev. B MG3702xA MM
1. Allow a 30 minute warm up, then run self-test.
• If error 108 is not displayed, the problem is cleared.
• If error 108 is displayed, go to Step 2 .
2. Remove the bottom cover.
3. Measure the DC level on mother board on the A8 connector J11 pin 3A with a DVM.
4. If the level is above 3V then replace A8 PCB. Allow a 30 minute warm up, then run self-test.
• If error 108 is not displayed, the problem is cleared.
• If error 108 displays, go to Step 6 .
5. If the level is below 1V then replace A7 PCB. Allow a 30 minute warm up, then run self-test.
• If error 108 is not displayed, the problem is cleared.
• If error 108 displays, go to Step 6 .
6. If error 108 is displayed, contact your local Anritsu service center for assistance.
1. Using a coaxial cable with BNC connectors, connect the rear panel
10 MHz REF IN
connector to the rear
panel
10 MHz REF OUT
connector.
2. Disconnect the MCX cable
WF101
from
A6J6
.
3. Using an oscilloscope, verify the presence of a 10 MHz signal at the end of the MCX cable
W158
.
The signal amplitude should be > 0.2 volts peak-to-peak (into 50 ohms).
• If the signal is present, replace the A7 PCB.
• If the signal is not present, replace the MCX cable
W158
and inspect the BNC
10 MHz REF IN
connector.
1. Replace the A6 PCB, and run self-test.
• If no error message is displayed, the problem is cleared.
• If error message 121 or 122 are displayed, contact your local Anritsu service center for assistance.
Table 5-13. Error Message 108 Crystal Oven Cold
Description: Indicates that the 100 MHz crystal oven on the A7 Reference/Coarse loop PCB has not reached
operating temperature. The MG3702xA is still operable, but frequency accuracy and stability may be degraded.
Table 5-14. Error Message 109 100MHz Reference is not Locked to the External Reference
Description: Indicates that the reference loop is not phase-locked to the external 10 MHz reference. The
reference loop may phase-lock to the internal 100 MHz time base; consequently, the MG3702xA would continue to
operate normally.
Table 5-15. Error Messages 121 and 122
Error message 121: Unleveled Indicator Failed
Error message 122: Level Reference Failed
Description: These error messages indicate a failure of the leveled detector circuitry or the level reference
circuitry. Each of the other error messages indicates a problem in the circuitry on the A6 ALC PCB that provides
control of the RF output power level. Also, a warning message on the display may appear when the RF output is
unleveled.