Keysight 9000 Series Service Manual page 76

Chapter 4: Troubleshooting
Keyboard Trouble Isolation Procedure
Keyboard Trouble Isolation Procedure
Use this procedure only if you encounter key failures in the keyboard self test procedure. If any knobs
fail, replace the keyboard assembly.
Disconnect the power cord and remove the cover.
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2 Remove the front panel assembly.
See chapter 6 for instructions.
3 Remove the keyboard assembly from the front panel assembly. Partially re-assemble the front panel
assembly, including the flat-panel display and lens, but omitting the keyboard. Re-attach the partial
assembly to the chassis.
Be sure to reconnect the display video cable and the backlight inverter cables. See chapter 6 for
instructions on removing and disassembling the front panel.
4 Separate the elastomeric keypads from the keyboard assembly.
C A U T I O N
CONTAMINATION CAN CAUSE INTERMITTENT OPERATION!
Be careful not to contaminate the key side of the PC board or the keypads. Dust and fingerprints on
these parts may cause intermittent key operation.
5 Set the keyboard assembly on an antistatic electrical insulated surface.
6 Connect the keyboard cable to the scope interface board in the chassis.
You may need to set the chassis on its side to allow proper routing of the cables without straining them.
7 Reconnect the power cable and apply power.
8 Enable the graphical interface, then start the keyboard test as described in the Primary Trouble Isolation
section of this chapter.
9 Carefully short the PC board trace with a paper clip or screwdriver at each non-operating key (as
determined by keyboard test), and look for an appropriate response on the display.
• If the display responds as though a key were pressed, replace the elastomeric keypad.
• If the display does not respond as though a key were pressed, replace the keyboard.
10 Re-assemble the oscilloscope.
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