Installation guide

Troubleshooting
Getting Started with Troubleshooting
1-12
Symptom: If the Display is Bright, but without Characters
❏ Check that the signal generator is powered-on and the front panel green LED is lit. If the green LED is not
lit, refer to the Power Supply Troubleshooting section in this manual. Press any front panel key to disable
the screen saver.
— If the green LED is lit and the display is too bright, try adjusting the contrast controls on the front
panel. Refer to “Symptom: If the Display is Dark” on page 1-10.
— If adjusting the contrast controls has no effect, use an oscilloscope to check the signals in Table 1-6. The
pulse-state signals listed are control, clock, and data lines for the A2 Display. Probe the signals on the
back of the ribbon cable on P1 of the A3 Front Panel Auxilary Board.
— If the signals in Table 1-6 are correct, replace the A2 Display.
(Refer to “A2 Display” on page 2-10.)
— If the signals are incorrect, use an oscilloscope to check J30 on the A23 Motherboard for signals shown
in Table 1-7.
Table 1-6
Signal State
J1-7 VLCD approximately 21 Vdc
J1-4 LCD_EN_L >3 Vdc
J1-5 5.2 Vdc
J1-8 to 15
Refer to Figure 1-4.
Table 1-7
Signal State
J30-3 VLCD approximately 21 Vdc
J30-5 LCD_EN_L >3 Vdc
Pulsing Activity
LCD_DATA
J1-8 to 15,
J30-13, 14, 17, 18, 23, 24, 27, 28,
J15-24, 25, 28, 29, 32, 33, 86, 90
Refer to Figure 1-4.
Pulsing Activity
LCD_CLK
J1-3, J30-4, J15-94
Refer to Figure 1-5.
Pulsing Activity
LCD_LOAD
J1-2, J30-8, J15-36
Refer to Figure 1-6.
Pulsing Activity
LCD_FRAME
J1-1, J30-7, J15-93
Refer to Figure 1-7.