NEC Neax 2400 Imx System Operations And Maintenance Manual

							CHAPTER 5 NDA-24238
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FAULT REPAIR PROCEDURES
4.1 Check Point 
When repairing a unit fault, consider the following items:
(1) Speech paths and control paths in the unit are connected to line/trunks via the MUX circuit cards. Be sure
to check the alarm lamps on the MUX circuit cards, and check to see if the front cable between each MUX
circuit card and TSW circuit card is connected correctly. Figure 5-5 and Figure 5-6 show the block dia-
gram within the unit.
(2) The MUX circuit cards are operating in the ACT/STBY modes under control of the CPU circuit. When
the ACT-side CPU has detected a fault in the ACT-side MUX circuit card, CPU changeover is executed
and the ACT/STBY mode of the Speech Path System is also changed over. When both of the MUX circuit
cards have become faulty, all the lines/trunks in that unit are placed into make-busy state. (If a PFT circuit
card is located in that specific unit, the PFT is activated.) Figure 5-7 shows the location of the MUX cards.
(3) When both units in a specific PIM are faulty, it is possible that the PWR circuit card mounted in that spe-
cific PIM is faulty. In such a case, refer to Section 8, Power Supply Fault.
Figure 5-5   Unit Control Block Diagram (Dual Configuration)
MUX0
Clock
(B)
(A)
Speech
Path To
TSW/INT
MUX1
LC/TRK
LC/TRK
PM
Line/
Trunk
Circuit Card Control of 
CPU No. 0
ACT/STBY of
CPU No. 0Clock
(B)
Speech
Path
(A)To
TSW/INT
Control of 
CPU No. 1
ACT/STBY of
CPU No. 1
SYMBOLS
:  Circuit Card
:  Control on ACT/STBY of Speech Path Systems
:  Control on ACT/STBY of Clock Systems
(A)
(B) 
						

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FAULT REPAIR PROCEDURES
Figure 5-6   Unit Control Block Diagram (Single Configuration)
Figure 5-7   MUX Card Locations
LC/TRK
LC/TRK
PM
Line/
Trunk
Circuit Card
MUX X
To
TSW/INTClock
Speech
Path
(A)
Control of
CPU
MUX (PH-PC36) card is mounted
in Slot No. 13 and/or 14 of each
PIM.
MUX 0MUX 1UNIT = 2
UNIT = 3 PIM 3
13 IMG0/1/2/3
Front View14
MUX 0MUX 1UNIT = 0
UNIT = 1 PIM 213
14
MUX 0MUX 1UNIT = 2
UNIT = 3 PIM 113
14
MUX 0MUX 1UNIT = 0
UNIT = 1 PIM 013
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FAULT REPAIR PROCEDURES
4.2 Unit Fault - Fault Related to Speech
Faulty Situation:
 Noise, one-way speech, no tone, etc. occurs only within a unit.
 Even if dialing has started, dial tone does not stop.
(1) For Dual Configuration
Check by replacing the MUX (PH-PC36)
circuit card.Replace the MUX circuit card referring to 
Section 3.3.2, MUX Card Replacement 
Procedure, in Chapter 4.
After replacement of the MUX
circuit card, make a station-to-
station call in the faulty unit and
see if speech is normal.Place the MUX circuit card into ACT mode
by flipping the MBR key on the active GT
(PH-GT09) card. Refer to Section 12.1.6,
Manual System Changeover of Speech Path
System, in Chapter 6.
Check by replacing the TSW circuit card. Replace the TSW circuit card by referring to 
Section 2.3.2, TSW Card Replacement 
Procedure, in Chapter 4.
After replacement of the TSW
circuit card, make a station-to-
station call in the faulty unit and
see if speech is normal.Place the TSW circuit card into ACT mode 
by flipping the MBR key on the active GT 
(PH-GT09) card. Refer to Section 12.1.6, 
Manual System Changeover of Speech Path 
System, in Chapter 6.
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FAULT REPAIR PROCEDURES
Check the line/trunk circuit cards mounted
in the unit to see if they are faulty.Set the MB switch of the line/trunk circuit card
UP and extract it from its mounting slot.
Make a station-to-station call and see if a fault
occurs.
Perform this check on an individual basis.
If the fault has stopped occurring,
the circuit card extracted at that
time is faulty. Replace the circuit
card with a spare.
If the fault continues, check the
next circuit card.
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FAULT REPAIR PROCEDURES
(2) For Single Configuration
Check by replacing the MUX (PH-PC36)
circuit card.Replace the MUX circuit card by referring to
Section 3.3.2, MUX Card Replacement
Procedure, in Chapter 4.
After replacement of the MUX
circuit card, make a station-to-
station call in the faulty unit and
see if speech is normal.Press the RESET button on the EMA card
(*D).
Check by replacing the TSW circuit card. Replace  the  TSW  circuit  card  referring  to
Section 2.3.2, TSW Card Replacement
Procedure, in Chapter 4.
After replacement of the TSW
circuit card, make a station-to-
station call in the faulty unit and
see if speech is normal.Press the RESET button on the EMA card
(*D).
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FAULT REPAIR PROCEDURES
Check the line/trunk circuit cards mounted
in the unit to see if they are faulty.
Perform this check on an individual basis.Set the MB switch of the line/trunk circuit
card UP and extract it from its mounting slot.
Make a station-to-station call and see if a fault
occurs.
If the fault has stopped, the
circuit card extracted at that time
is faulty. Replace the circuit card
with a spare.
If the fault continues, check the
next circuit card.
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FAULT REPAIR PROCEDURES
4.3 Unit Fault - When Dial Tone (DT) Cannot Be Heard
Faulty Situation:
 Dial Tone (DT) cannot be heard except within a unit.
[4-T] Both MUX Failure / [4-S] MUX Ready Failure
[23-Y] MUX Clock Failure
Note:For dual system configuration, if a system message indicates that both systems are faulty, first repair
the fault in the indicated system and then proceed to repair the PIM in the other system.
(1) For Dual Configuration
Check to see if the MUX (PH-PC36) circuit
card is making poor contact.Set the MUX circuit card into STBY mode by
flipping the MBR key on the active GT (PH-
GT09) card. Refer to Section 12.1.6, Manual
System Changeover of Speech Path System, in
Chapter 6.
Set the MB switch of the MUX circuit card UP.
Extract the MUX circuit card from its mounting
slot and clean the contact portion.
If cleaning cannot be done, repeat insertion and
extraction of the circuit card two or three times.
Set the MB switch of the MUX circuit card UP
and insert the circuit card into its mounting slot.
Set the MB switch of the MUX circuit card
DOWN.
Check to see if a station-to-station connection
can be set up within the faulty unit.
Check by replacing the MUX circuit card
with a spare.Place the MUX circuit card into STBY mode by
flipping the MBR key on the active GT (PH-
GT09) card. Refer to Section 12.1.6, Manual
System Changeover of Speech Path System, in
Chapter 6.
Replace the MUX circuit card. Refer to Section
3.3.2, MUX Card Replacement Procedure, in
Chapter 4.
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FAULT REPAIR PROCEDURES
Place the MUX circuit card into ACT mode by
flipping the MBR key on the active GT (PH-
GT09) card. Refer to Section 12.1.6, Manual
System Changeover of Speech Path System, in
Chapter 6.
Check to see if a station-to-station connection
can be set up to identify the circuit card respon-
sible for the fault.
Extract all the line/trunk circuit cards from
their mounting slots in the unit. Insert the
cards back into their slots one after another
and see if the dial tone is heard each time.Extract all the line/trunk circuit cards from their
slots.
Note:Set the MB switch of the line/trunk
circuit card UP and extract.
Confirm the MUX ACT lamp on the MUX cir-
cuit card illuminates.
Set the MB switch of an extracted line/trunk
circuit card UP and insert the circuit cards into
their mounting slots one by one.
Confirm the OPE lamp of the inserted circuit
card illuminates by setting the MB switch
DOWN. If Dial Tone (DT) is heard, check
the next circuit card.
Make a station-to-station call and see if DT can
be heard. 
Note:Perform this check on the rest of the
circuit cards by inserting them into
their slots individually. If DT is not heard, replace the cir-
cuit card with a spare.
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FAULT REPAIR PROCEDURES
(2) For Single Configuration
Check to see if the MUX (PH-PC36)
circuit card is making poor contact.Set the MB switch of the MUX circuit card UP.
Extract the MUX circuit card from its mounting
slot and clean the contact portion.
If cleaning cannot be done, repeat insertion and
extraction of the circuit card two or three times.
Set the MB switch of the MUX circuit card UP
and insert the circuit card into its mounting slot.
Set the MB switch of the MUX circuit card
DOWN.
Check to see if a station-to-station connection
can be set up within the faulty unit.
Check by replacing the MUX circuit card
with a spare.Replace the MUX circuit card referring to Sec-
tion 3.3.2, MUX Card Replacement Procedure,
in Chapter 4.
Place the MUX circuit card into ACT mode by
flipping the MBR key on the active GT (PH-
GT09) card. Refer to Section 12.1.6, Manual
System Changeover of Speech Path System, in
Chapter 6.
Check to see if a station-to-station connection
can be set up to identify a circuit card responsi-
ble for the fault.
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FAULT REPAIR PROCEDURES
Extract all the line/trunk circuit cards from
their mounting slots in the unit. Insert the
cards back into their slots one after
another and see if the dial tone is heard
each time.Extract all the line/trunk circuit cards from
their slots. 
Note:Set the MB switch of the line/trunk
circuit card UP and extract.
Confirm the MUX ACT lamp on the MUX
circuit card illuminates.
Set the MB switch of an extracted Line/Trunk
circuit card UP and insert the circuit cards
into their mounting slots one by one.
Confirm the OPE lamp of the inserted circuit
card illuminates by setting the MB switch
DOWN.
Make a station-to-station call and see if dial
tone can be heard. 
Note:Perform this check on the reset of
the circuit cards by inserting them
into their slots individually. If DT is heard, check the next
circuit card.
If DT is not heard, replace the
circuit card with a spare.
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