ATT System 25 Installation And Maintenance Manual
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Figure 4-6.Clearing Tie Trunk Troubles (Sheet 2 of 5)
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Figure 4-6.Clearing Tie Trunk Troubles (Sheet 2 of 5)
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Figure 4-6. Clearing Tie Trunk Troubles (Sheet 1 of 5) 4-55
MAINTENANCE [6] [7] [8] [9] [10] Figure 4-6.Clearing Tie Trunk Troubles (Sheet 2 of 5) 4-56
MAINTENANCE Figure 4-6. Clearing Tie Trunk Troubles (Sheet 3 of 5) 4-57
MAINTENANCE Figure 4-6.Clearing Tie Trunk Troubles (Sheet 4 of 5) 4-58
MAINTENANCE Figure 4-6. Clearing Tie Trunk Troubles (Sheet 5 of 5) 4-59
MAINTENANCE Figure 4-7.Clearing Paging Equipment Troubles
MAINTENANCE Clearing System-Detected Troubles Most troubles are detected through the Alarm LED located on the Attendant Console, the Error Log, and, in some cases, the LEDs on the circuit packs (CPs). The following is a list of system troubles. Each item in the list is described in this section. Complete System Failure Common Control Trouble Circuit Pack Trouble Frontplane Ribbon Connector Trouble (Release 1 Only) Power Supply Trouble Fan Assembly Trouble Overheating Trouble Backplane and CabinetTrouble Emergency Transfer Unit Trouble. Complete System Failure A complete system failure is caused by a catastrophic failure in the Common Control circuitry, the power supply, the backplane, or the cabinet. Refer to the relevant procedures below in the event of such a failure. Complete system failures are rare; most failures are of a noncritical component, such as a port on a CP. Common Control Trouble Failure of a the Common Control CP (that is, CPU/Memory or Service Circuit) is critical and requires replacement of the faulty pack(s). Failure of these CPs can affect the entire system and may cause the Emergency Transfer Unit (ETU) to activate. 4-61
MAINTENANCE Failure of the CPU/Memory CP at power-up generates the following type of error message: FAIL: : : : The bracketed fields contain the following information: l is CPU/Memory l is one of the following: RAM TEST ROM TEST AA INTERFACE DUART TEST REAL-TIME-CLOCK TEST BUS ERROR WORK CYCLE DPRTEST MMU TEST AA RESET STUCK : SC? l specifies the specific location of the failure, such as the address of a failed integrated circuit. A representative Common Control failure message would be as follows: FAIL: CPU: RAM TEST: IC26: This message identifies the failure as a Random Access Memory (RAM) test failure in integrated circuit 26 occurring on the CPU/Memory CP. After partial failure, the system continues to operate and the green LED on the CPU/Memory CP flashes normally. 4-62
MAINTENANCE After total failure, the system ceases to operate and the green LED on the CPU/Memory CP may not flash. Failure can also be verified by checking the LEDS on each CP. If either a partial or total Common Control failure is detected, remove and then restore system power.This procedure forces the system to perform a warm restart. If the failure exists after system restart, remove power again and reseat CP suspected of being faulty. (Be sure to press in all socketed devices to ensure a firm connection.) Restore system power. If a Common Control failure continues to exist, one of the CPs must be replaced. To determine which CP to replace, check the messages on the SAT and in the Error Log and check the LEDs on the CPs. Common Control error messages sometimes appear on the SAT automatically during power-up testing.If the Common Control is experiencing serious failure, error messages may appear only on the SAT and not be sent to the error log. For Release 1 systems, a Memory CP problem could be caused by (1) a fault in the frontplane connector to the Call Processor CP or (2) a problem on the Call Processor CP itself. A Memory CP problem does not necessarily indicate a fault in the Memory CP. To replace a Common Control CP, follow the preceding instructions. Be sure to save translations on tape before removing power. For Release 1 systems, replacing either the Call Processor or Memory CP also requires that the frontplane connector be disconnected and then reconnected. After replacing the CPU/Memory CP, it is mandatory to force a Cold Start or Limited Cold Start. The Cold Start initializes the new CPU/Memory CP with the system’s CP configuration as well as clears all status and error logs. Old information may have been stored on the replacement CP; therefore, you should then do a tape restore to restore to the original translations (Note! You must have a DTU to do this). Circuit Pack Trouble Most CP troubles result in user complaints.User complaints are discussed under “Clearing User-Reported Troubles” in this section. Diagnosis of user complaints is aided by messages in the Error Log and LEDs on the CPs. 4-63
MAINTENANCE Once a faulty CP is identified, it can be replaced using the procedures in “Reseating and Replacing Circuit Packs” under “Routine Maintenance. ” Refer to the information in “Circuit Pack LEDs” under the “General Maintenance Information” to understand the meaning of the CP LEDs. . If the Error Log notes an error related to the touch-tone receivers, the receivers are performing below system requirements. Touch-tone receiver problems are due to a faulty Service Circuit (ZTN85 or ZTN131 [R3]) or Tone Detector (TN748). Replace the faulty CP. Frontplane Ribbon Connector Trouble (Release 1 Only) The frontplane ribbon connector is a flat cable connecting the Call Processor and Memory CPs at their front edges. To reattach or replace this cable, follow these steps: 1.Remove power from the system. 2. Pull the exposed tab on the cable from one of the CPs. This exposes a second tab at the other end of the cable. 3. Pull the second tab to remove the cable entirely. 4.Replace the cable in the reverse manner. (The cable is keyed for correct placement.) Power Supply Trouble If a major malfunction occurs, the system may activate the 109 Emergency Transfer Unit. With this condition, the system may be nonfunctional, even though the green LEDs on CPs in the other cabinets remain lighted. Failure of the power supply in a cabinet containing only port CPs (Cabinet 2 or 3) will shut down all devices connected to that cabinet but will not shut down the entire system. Check the green LED on PS (visible through the fan slots on the front door). If extinguished, PS is shut down.Remove ac power from the cabinet for about 3 minutes. Turn on ac power. Green LED lighted, PS overheated (fan defective), or current overload. Check all boards in cabinet for problems. 4-64