Installation guide

Troubleshooting
Getting Started with Troubleshooting
1-18
Symptom: If the Screen Saver is Not Functioning
The screen saver delay may be set for any integer from 1 to 12 hours. The A12 CPU controls the screen saver
by pulling the LIGHT_EN line low.
• Ensure that the signal generator is powered-on and that the front panel green LED is lit.
— If the green LED is lit, the delay time has elapsed, and the display hasn’t gone dark:
a. Check the LIGHT_EN signal at J30-20. (Refer to Figure 1-11.)
— If the signal is a TTL low, replace the A4 Inverter.
(Refer to “A4 Inverter” on page 2-16.)
— If the signal is a TTL high:
a. Check J15-37 of the A23 Motherboard. (Refer to Figure 1-9.)
— If the signal is a TTL high, replace the A12 CPU.
(Refer to “A12 CPU” on page 2-30.)
— If the green LED is not lit, refer to “Power Supplies” on page 1-23.