
8712ET/ES and 8714ET/ES Troubleshooting and Block Diagrams
RF Network Analyzers Category 1 Failures: Dead or No Display
Service Guide 4-7
Category 1 Failures: Dead or No Display
This category of failure usually involves one of the following:
• defective A6 power supply
• defective A2 CPU
• poor contact with the rear plane connector board
• digital failure in any board assembly
• defective display
Troubleshooting the Power Supply Assembly (A6)
Begin here if the problem appears to be power supply related.
Check the Rear Panel LEDs
Switch the analyzer's line power on. Check the condition of the two LEDs visible through
the hole in the rear panel to the right of the AC power plug.
1. If the green LED is on and the red LED is off
This represents a normal condition. Go to “Measuring the Power Supply Voltages” on
page 4-8 to confirm that the power supplies are functioning properly.
2. If neither LED is on
Check the line fuse, located in a holder above the AC power jack, and replace it with the
spare provided if necessary. Check the AC power line. If the LEDs are still off, replace
the power supply.
3. If the green LED is on, the red LED is on steadily, and the fan is off
Check the line voltage selector switch, located below the AC power jack. If the setting is
correct, remove the power supply/display assembly and make sure that the cable from
the on/standby switch to the power supply assembly is connected.With the power
supply/display assembly outside the analyzer, plug it in and switch the analyzer's line
power on.
a. If the fan is still off
Check the four green power supply LEDs visible from the right side of the display
enclosure (as viewed from the front). If the LEDs are on, the fan is probably broken.
Replace the fan or the entire power supply assembly.
4. If the green LED is on, the red LED is on steadily, and the fan is on
Go to “Measuring the Power Supply Voltages” on page 4-8. Note that it is normal for
both the green and red LEDs to be on when the power switch is in STANDBY, but not
when the switch is in the on position.
Commenti su questo manuale