There is one clock+ board in the system.
 Caution -
Caution - The clock+ board is not hot-pluggable. You must halt the operating system and turn off AC power before replacing the clock+ board.
| Indication | Test/Procedure | Reference | 
|---|---|---|
| System will not boot 
 | Examine LED displays. | See Table 9-1. | 
| Clock+ board yellow "service" LED does not light during POST or remains lighted after POST 
 | Check clock+ board. | 
 | 
| System and board LEDs do not flash, or fail POST repeatedly with random LED patterns 
 | Check clock+ board and power supplies. | See Table 10-6. | 
| TTY port A does not respond | Check settings for the port. Replace peripheral power supply. | See "Using a Terminal". |