1. On a cabinet, the alarm driving signals on the LAMP1 or LAMP2 interface of the EFI control the cabinet indicators. Therefore, analyze why the alarm indicators on the EFI are off before you analyze why the cabinet indicators are off.
2. The alarm indicators on the EFI of a slave subrack are under the control of the master subrack. Therefore, the problem may lie in the indicator/alarm concatenation between the master and slave subracks. The subracks with the problem are in one cabinet. Therefore, engineers doubt that there is no indicator/alarm cascade cable between the two cabinets.