Service Guide N5227-90001 4-15
PNA Series Microwave Network Analyzers Troubleshooting
N5227A Front Panel Troubleshooting
Checking the RPG (Front Panel Knob)
To c h e ck t h e RPG k n o b :
1. Press the UTILITY key.
1. Rotate the knob and check for a fluid movement of numbers on the analyzer display.
1. If the movement of numbers is not smooth or no numbers appear at all, suspect a faulty A1 front panel
interface board. To replace the A1 front panel interface board, refer to “Removing the A1 Front Panel
Interface Board and Keypad Assembly” on page 7-8.
A3 Display Test
The display should be bright with all annotations and text readable. The display test allows you to check for
non-functioning pixels and other problems.
NOTE If the display is dim or dark, refer to “Troubleshooting LCD Display Problems” on page 4-12.
What Is a Damaged Pixel?
A pixel is a picture element that combines to create the image on the display. A pixel is about the size of a
small pin point.
A damaged pixel is a pixel that has a constant blue, green, black, or red appearance that will not change.
How to Run the Display Test
To run the display test, perform the following:
Press UTILITY , then , then , then .
A multi-color screen is displayed. Be prepared to look for the symptoms described in “How to Identify a
Faulty Display.” Follow the instructions on the screen.
How to Identify a Faulty Display
A display is considered faulty if:
• More than 0.002% of the total pixels have a constant blue, green, red, or black appearance that will not
change.
• Three or more consecutive pixels have a constant blue, green, red, or black appearance that will not
change.
If the A3 display assembly is determined to be faulty, replace it. Refer to “Removing the A3 Display
Assembly and the Touchscreen” on page 7-9.
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