Keysight Technologies E8257D Service Manual page 34

Troubleshooting
Troubleshooting Assembly–Level Problems
Symptom: Hardkeys or softkeys do not work
The A1 Keyboard contains the hardkeys and softkeys switches. The keys are
arranged in a matrix (shown below) with the control lines KEYCOLx and
KEYROWx on the x and y axis. When you press a hardkey or softkey, one cell of
the matrix is activated; the normally TTL low KEYROWx of the active cell pulses
high, and the normally TTL high KEYCOLx of the active cell pulses low.
KEYCOL0
KEYROW0 softkey 3
KEYROW1 softkey 2
KEYROW2 softkey 1
KEYROW3 softkey 4
KEYROW4 softkey 6
KEYROW5 softkey 5
KEYROW6 N/A
KEYROW7 softkey 7
1. Ensure that the front panel green power on LED is on. If it is not on, refer to
2. To ensure the signal generator is not being controlled remotely, press the
3. Use an oscilloscope to monitor the KEYCOLx and KEYROWx pins of the key
34
Signal
J9−4 LCD_ENABLE_H
J9−5
J9−1, 2, 3, 8 to 15
If these signals are good, replace the LCD.
If these signals are not good, replace the power switch/flat panel interface
board.
KEYCOL1 KEYCOL2
N/A Cont Up
Incr/Set Cont Down
Up N/A
N/A N/A
N/A Local
N/A Return
N/A N/A
N/A Preset
"Power Supply Troubleshooting" on page
Local hardkey.
that is not working at P13 on the motherboard. Use the following table to
identify the appropriate pin number:
KEYCOL pins should be a TTL high
KEYCOL0 P13–1
KEYCOL1 P13–3
KEYCOL2 P13–5
KEYCOL3 P13–7
KEYCOL4 P13–9
KEYCOL5 P13–11
KEYCOL6 P13–13
KEYCOL7 P13–15
E8257D/67D, E8663D PSG Signal Generators Service Guide
State
>3 Vdc
5.2 Vdc
Refer Figure 1-1 on page
KEYCOL3 KEYCOL4
N/A LF Out
Ampl Ampl Menu Mode Setup Aux Fctn
Freq Sweep List Mode
Right Arrow Help
Hold Mod On/Off 4
Down Arrow N/A
Left Arrow RF On/Off
N/A N/A
37.
KEYROW pins should be a TTL low
KEYROW0
KEYROW1
KEYROW2
KEYROW3
KEYROW4
KEYROW5
KEYROW6
KEYROW7
33.
KEYCOL5 KEYCOL6 KEYCOL7
N/A I/Q Pulse
FM/ϕΜ
Mux AM
Save Recall Trigger
5 6
7 8 9
0 . +/-
1 2 3
P13–17
P13–19
P13–21
P13–23
P13–25
P13–26
P13–24
P13–22