NEC Neax 2400 Imx System Operations And Maintenance Manual

							CHAPTER 4 NDA-24238
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UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE
6. Fuse Replacement
The system uses the fuses shown in Figure 4-28 as a protection against an overload resulting from a short cir-
cuit.
Figure 4-28   Fuses Used by System
When excessive current is applied to a PWR circuit card, the related fuse is blown. The blown fuse after a fault
can be confirmed as shown in Figure 4-29.
Figure 4-29   Blown Fault Example
The purpose of fuses is to let them blow before the components are damaged. If any fuse gets blown, replace
it immediately with a new one using the following procedure:
(1) Confirm the blown fuse via the system message [6-A] or MJ lamp on the top of IMG0.
(2) Replace the fuse with a new one, referring to Figure 4-30 and Figure 4-31.
(3) Determine the cause of the blown fault, referring to Figure 4-32 (case of RGU fuse) or Figure 4-33 (DC-
48V fuse.)
1.5A
12.5V25A
If a fuse is blown, 
this area turns white.
A normal fuse A blown fuse 
						

							NDA-24238 CHAPTER 4
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UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE
Figure 4-30 shows the location of fuses within the system. In Chapter 4-30, the fuses are indicated by   or  .
Figure 4-30   Fuse Locations Within System
NECNEAX 2400 IMS
PZ-M377
3.2A 5.0A
PZ-M3695.0A
..... .....
..... .....
PZ-PW92
5.0A 25A
25A
5.0A0.5A
PA-PW54
PA-PW555.0A
0.5A
25A
PBX [Front View] 
						

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UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE
In the TSWM, the fuse shown in Figure 4-31 is used for the PWR SW (PH-PW14) card, which is housed in
Slot No. 00 and/or 01.
Figure 4-31   Fuse Location Within TSWM
 PH-PW14
(PWR SW)
FUSE:    15A
TSWM
PBX (IMG1)
Front View

 
						

							NDA-24238 CHAPTER 4
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UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE
Perform the procedure in Figure 4-32 to confirm the cause of the RGU fuse blown fault.
Figure 4-32   RGU Fuse Blown Fault Flowchart

Start
Visual check: No pin contacting
 or backboard melting?
OPE  Lamp (green) of 
each LC card  remains lit?
Replace the blown fuse with a new
one. The fuse is blown again?Yes
Yes
Yes
Yes YesNo
1.  Turn ON (UP) the MB key
     on the LC card.
2.  Remove the card from the PIM.
3.  Replace the fuse with a new one.
 Turn ON (UP) the MB
 keys on all LC cards,
and  remove them from the
PIM. (Only PWR cards are
inside the PIM)
Turn ON (UP) the MB
keys on the whole LC cards,
and  remove them from the
PIM. (Only PWR cards are
inside the PIM)
The replaced fuse
 is blown again?

Perform station-to-station 
connections within the PIM.
Is any fuse blown?

Perform station-to-station 
connections within the PIM.
Is any fuse blown?No
No No No No
No
Yes
YesNo

Fault in LC card that accompanied
the fuse blowing.

Fault of LC card that accompanied 
the fuse blowing.

Probable Cause: Not  confirmed.
Needs further observation of the fault

There is a short circuit
on the backboard of the PIM.

Fault in LC card that accompanied 
the fuse blowing.

Fault of PWR card.

Perform system initialization
after inserting all removed cards.

Fault of LC card
that was removed
Replace the blown fuse
with a new one.
Replace the blown fuse
with a new one.
Replace the PWR card
Yes
Insert the removed cards
one by one (into the PIM).
Is any fuse blown?
The replaced fuse is 
blown again?
 Fuse is still blown? NoYes

 
The replaced  fuse
 is blown again? 
						

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UNIT/CIRCUIT CARD REPLACEMENT PROCEDURE
Perform the procedure in Figure 4-33 to confirm the cause of the DC-48V fuse blown fault.
Figure 4-33   DC -48V Fuse Blown Fault Flowchart
Start
Visual check: No pin contacting
 or backboard melting?
OPE  Lamps (green) of 
LC/TRK/NCU cards remain lit?
Make sure in which module 
the fuse has blownNo
1.  Turn ON (UP) the MB key
     on the circuit card.
2.  Remove the card from the PIM.
3.  Replace the fuse with a new one.
Turn ON (UP) the MB
keys on the whole circuit
cards, and remove them from
the PIM. (Only PWR cards
are inside the PIM)
Turn ON (UP) the MB
keys on the whole circuit 
cards, and remove them from
the PIM. (Only PWR cards 
are inside the PIM)
The replaced  fuse
 is blown again?No
No
No No

Fault of  circuit card that
accompanied the fuse blown.
Perform system initialization
after inserting all removed cards.

Fault of circuit card
that was removed
Replace the blown fuse
with a new one.
Replace the blown fuse
with a new one.Yes
Yes
 Yes
Insert the removed cards 
one by one  (into the PIM).
Is there any fuse blowing?
The replaced  fuse
is blown again?
The fuse is still blown?


There is a short circuit on the 
backboard of the PIM.

Fault of PWR card.
Replace the PWR cardYes
YesLPM / TSWM / PIM
No

Fault of circuit card that
accompanied the fuse blown.

Perform system initialization
after inserting all removed cards. Yes
Insert the removed cards 
one by one  (into the PIM).
Is any fuse blown?

 
						

							NDA-24238 CHAPTER 5
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FAULT REPAIR PROCEDURES
CHAPTER 5 FAULT REPAIR PROCEDURES
This chapter provides information on how to repair the fault(s) within the system. If any of the components or
equipment listed in Table 5-1 has a failure, move on to the repair procedure explained for each faulty condition.
Table 5-1  Fault Repair Procedure Quick Reference
FAULTY ITEM FAULTY SITUATION REFERENCE SECTION
Line Fault DP/PB Telephone Dial tone is not heard.Section 1.3, Line Fault - When Dial 
Tone (DT) Cannot Be Heard
Dialing results in a wrong 
connection.Section 1.4, Line Fault - When 
Dialing Results in Wrong 
Connection
Bell does not ring.Section 1.5, Line Fault - When Bell 
Does Not Ring
Answer/speech cannot be 
made.Section 1.6, When Call Cannot Be 
Answered and Speech Cannot Be 
Made
D
termDterm cannot be operated.
 Operations are abnormal.Section 1.7, Dterm Fault
Trunk Fault  No connections can be set up.
 PB/DP signals are erroneously received or set out 
from ORT/SND.
 No three-way calling can be made on CFT, or noise 
gets in a established connection.
 A connection results in no speech.
 Noise gets in a established connection.Section 2.3, Trunk (ORT, SND, 
CFT) Fault and Section 2.4, Trunk 
(COT, TLT, DTI) Fault
ATTCON/DESKCON  No speech can be made.
 No control operations can be made.Section 3.3, ATTCON/DESKCON 
Fault
Unit Fault Faults related to speech.Section 4.2, Unit Fault - Fault 
Related to Speech
Dial tone is not heard.Section 4.3, Unit Fault - When Dial 
Tone (DT) Cannot Be Heard
The ACT MUX card side has become faulty and system 
changeover has been executed.Section 4.4, Unit Fault - ACT-Side 
MUX Card Is Faulty and System 
Has Changed Over 
						

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FAULT REPAIR PROCEDURES
Speech System Fault Faults related to speech.Section 5.2, Speech Path System 
Fault - Fault Related to Speech
Dial tone is not heard.Section 5.3, Speech Path System 
Fault - When Dial Tone (DT) 
Cannot Be Heard
STBY side is faulty.Section 5.4, Speech Path System 
Fault - STBY Side Has Become 
Faulty
Control System Fault Fault occurs occasionally at the ACT side.Section 6.2, Control System Fault - 
Fault Occurs Intermittently
STBY side is faulty.Section 6.3, Control System Fault - 
STBY Side Is Faulty
Alarm Indication Fault No fault indication is made on the Alarm Indicator 
Panel.Section 7.2, Fault of Alarm 
Indicating Panel
Fault is not detected.Section 7.3, Fault That Cannot Be 
Detected
Power Supply Fault Fuse for RGU/-48V has blown.Section 8.2, Fuse Blown Fault
The circuit breaker of PWR supply is off.Section 8.3, Circuit Breaker OFF 
Fault in PWR Supply
Alarm lamp on the PWR supply is lit.Section 8.4, Fault of Alarm Lamps 
on PWR Supply
Fan  Unit  Fault  Fan are not activated even if the temperature has risen 
higher than a predetermined degree.
 Fans are not activated even if the FAN START switch 
is set to AUTO position.Section 9.2, Fan Unit Fault
Tone Fault Tone is distorted.Section 10.2, Tone Fault
System Down Fault Cause for the fault cannot be identified.Section 11.1, When Cause for Fault 
Cannot Be Identified
The faulty circuit card can be detected.Section 11.2, When Faulty Circuit 
Cards Can Be Assumed From 
System Message
CCIS Line Fault  A Specific CCH/CCT card is faulty. When the signal 
transmission line is a digital line, transmission/re-
ceiving of control signals cannot be performed. 
 When the signal transmission line is an analog line, 
transmission/receiving of control signals cannot be 
performed.Section 12.3, Specific CCH/CCT 
Card Is Faulty and
Section 12.4, Fault of CCH, DTI 
and Related Flat Cable Table 5-1  Fault Repair Procedure Quick Reference (Continued)
FAULTY ITEM FAULTY SITUATION REFERENCE SECTION 
						

							NDA-24238 CHAPTER 5
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FAULT REPAIR PROCEDURES
1. LINE FAULT
This section explains the fault repair procedure in a case where only one specific station line is in any of the
faulty conditions listed in Ta b l e  5 - 2.
ISDN Line Fault  A specific DCH/PRT card is faulty.
 When the signal transmission line is a digital line, 
transmission/receiving of control signals cannot be 
performed.Section 13.3, Specific DCH/PRT 
Card Is Faulty and
Section 13.4, Fault of DCH, DTI, 
and Related Flat Cable
Hard Time Clock Fault EMA card is faulty.Section 14, Hard Time Clock Fault
Table 5-2  Line Fault Situation
FAULTY SITUATION REFERENCE SECTION
When Dial Tone cannot be heardSection 1.3, Line Fault - When Dial Tone (DT) Cannot Be Heard
When dialing results in a wrong connectionSection 1.4, Line Fault - When Dialing Results in Wrong 
Connection
When the bell does not ringSection 1.5, Line Fault - When Bell Does Not Ring
When call cannot be answered and speech cannot be 
madeSection 1.6, When Call Cannot Be Answered and Speech 
Cannot Be Made
D
term FaultSection 1.7, Dterm Fault Table 5-1  Fault Repair Procedure Quick Reference (Continued)
FAULTY ITEM FAULTY SITUATION REFERENCE SECTION 
						

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FAULT REPAIR PROCEDURES
1.1 Check Point
When repairing a line fault, consider the following items:
(1) Check alarm lamps on line circuit cards.
(2) When an outgoing call cannot be originated to a specific line/trunk or when an incoming call cannot be
terminated from a specific line/trunk, check Tenant Restriction Data (assigned via ATNR command) and
Route Restriction Data (assigned via ARSC command).
1.2 Line Control
Each line in a specific Line circuit (LC/ELC) card is controlled by the PM in that line circuit card. The
line circuit cards are controlled from the CPU via the MUX. Figure 5-1 shows the control route of line
circuit cards.
Figure 5-1   Controlling LC/ELC Circuit Cards and Speech Path
LC
MUX
TDSW/INT
GT
ISAGT
CPU
CPRTSW
MDF
LT Cable
LT Cable Control Signal
Speech Path
Control SignalLC/ELC
Ordinary Telephone/ Ordinary Telephone/
Symbols:
           :  Circuit Card                              :  Speech Path
          :  Control Signal
TSW:  PH-SW12                     GT:  PH-GT09
MUX:  PH-PC36                     ISAGT:  PZ-GT13
LC
PM
MUXLCLT Cable
LT Cable Control Signal
Speech PathLC/ELC
LC
PM
Dterm
Dterm 
						

							NDA-24238 CHAPTER 5
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FAULT REPAIR PROCEDURES
1.3 Line Fault - When Dial Tone (DT) Cannot Be Heard
Note:If a circuit card is replaced because only one line is
faulty, no other lines in that circuit card can be used
until the replacement is complete.
When OPE lamp on the LC circuit card
does not illuminateConfirm MB switch of the LC circuit card is in
ON position (UP).
Use ASDT command to confirm that station
data in the LC circuit card is assigned.
Replace the LC circuit card with a spare.
When BL lamp for each line is flashing or
illuminating on the LC circuit cardConfirm MB switch of the LC circuit card is in
ON position (UP side).
Use MBST command to confirm LC circuit
card has not been placed into make-busy state.
Use ASDT command to check the station data
assignment.
Replace the LC circuit card with a spare.
ATTENTIONContents
Static Sensitive
Handling
Precautions Required
START
A