NEC Neax 2400 Ipx System Operations And Maintenance Manual

NDA-24307 CHAPTER 5
Page 433
Issue 1
FAULT REPAIR PROCEDURES
10. FAN UNIT FAULT
This section explains the fault repair procedure where a fan in the Fan Unit (FANU) does not operate.
10.1 Check Point
(1) When repairing a FANU fault, exercise care about the following conditions. The fans (a total of 3) are
activated by operating the PWR SW key located on the PZ-M369. The conditions for starting the fan are
as follows:
With PWR SW key for the fan set to ON position: Always operating
With PWR SW key for...

CHAPTER 5 NDA-24307
Page 434
Issue 1
FAULT REPAIR PROCEDURES
10.2 Fan Unit Fault
Set the PWR SW key on the PZ-M369 to the ON position.
When the fan spins
Set PWR SW key to AUTO position, and short the thermal relay of the thermal
unit.
If the fan does not
operateCheck the connector cable between
the FANU and the thermal unit.
If the fan operates Replace thermal relay with a spare.
Disconnect the fan
connector of the cable for
the thermal unit.
Replace thermal relay with
a spare.
Connect the fan...

NDA-24307 CHAPTER 5
Page 435
Issue 1
FAULT REPAIR PROCEDURES
Figure 5-21   Circuit Diagram of Fan Unit and Thermal Unit
FAN 0FAN 1FAN 2
Power
Filter Fan Unit
FC0 FC1 FC2
POW
RLFUSE ALM
-48V
G
FEFUSE
FAN1
3
4
2 To PIM/
ON
OFF
AUTO
rl
F
FAN START Switch
Thermal Unit
Thermal
Relay
32
o C
89o F
Thermal
Relay
40
o  C
104o F
 
Thermal
Relay
70
o  C
158o F
Thermal
Relay
60
o  C
140o F
RL rl
GFEFA
LM
FAN
N P
-48V
EMNMJ
rl
To PIM To Display
Section
of TOPU
ISWM 

CHAPTER 5 NDA-24307
Page 436
Issue 1
FAULT REPAIR PROCEDURES
11. TONE FAULT
This section explains the fault repair procedure when any of the various tones cannot be heard in the whole
system.
11.1 Check Point
When repairing a tone fault, consider that the tone generator circuit is equipped in the TSW circuit card
and supplies tone. Check the alarm lamps of the TSW circuit card.
Figure 5-22 shows an example of the related trunking for dial tone connection.
Figure 5-22   Dial Tone Connection
TSW
DT
LC...

NDA-24307 CHAPTER 5
Page 437
Issue 1
FAULT REPAIR PROCEDURES
11.2 Tone Fault
Replace the TSW circuit card with a spare
and check.
When only Hold Tone is faulty.
If External Hold Tone source is in
use.Check the external equipment which sends out
hold tone.
Check cross connections on the MDF. Figure 5-
23 shows a block diagram of external hold tone
supply (optional).
Replace the PLO circuit card with
a spare.Set the MB switch of the PLO circuit card to
UP side and extract the circuit card from its
mounting...

CHAPTER 5 NDA-24307
Page 438
Issue 1
FAULT REPAIR PROCEDURES
Figure 5-23   External Hold Tone Supply Block Diagram
External 
   Tone
 Source
(Option)
To MUSIC 
connector
for the EMA
card (IMG0)
MDFNote 2
PLO 1TSW 00TSW 10TSW 03TSW 13TSW 02TSW 12TSW 01TSW 11
TSWM0 PIM 0 PIM 2 PIM 3
PIM 1
CLK 0CLK 1TSW 00TSW 10TSW 03TSW 13TSW 02TSW 12TSW 01TSW 11
TSWM1 PIM 0 PIM 2 PIM 3
PIM 1
This figure shows a block diagram of external hold tone supply (optional) in each Local Node (LN0 - LN3).  Note 1
- Symbols -...

NDA-24307 CHAPTER 5
Page 439
Issue 1
FAULT REPAIR PROCEDURES
12. SYSTEM DOWN FAULT
This section explains the fault repair procedure when both the CPU and TSW systems are faulty. Figure 5-24
shows the sequence of repair for system down fault.
Figure 5-24   System Down Fault Repair Sequence
When cause for the fault cannot be identified:
Section 12.1When faulty circuit cards can be assumed from
system message: Section 12.2
Check power supply.
Minimize system configuration.
Execute system initialization and...

CHAPTER 5 NDA-24307
Page 440
Issue 1
FAULT REPAIR PROCEDURES
12.1 When Cause for Fault Cannot Be Identified
 Check  power  supply  circuits. Check voltage (DC: -48 V ±5 V) at LOAD side 
of the rectifier.
Confirm that NFB (circuit breaker) on all PWR 
supplies is at ON position (UP side).
Check to see if there is any PWR supply to 
which the alarm lamp illuminates.
System Initialization by loading office data
and program data from the hard disk (Refer
to Section 12, Chapter 6.)
Service connections such...

NDA-24307 CHAPTER 5
Page 441
Issue 1
FAULT REPAIR PROCEDURES
(1) Check by minimizing the system configuration
Mount only the basic circuit cards in CPU 
No. 0 system and initialize.Remove all circuit cards from CPU No. 0
system except the basic circuit cards.
The circuit cards to be mounted are as follows:
•LN
CPU, EMA, GT, TSW, MUX
•ISW
CPU, EMA, IOGT, TSW, HSW
On the CPU Display Panel (DSP), set its SENSE
switch to “1.”
Press Reset (RST) button on the DSP.
CPU OPE lamp should be illuminated on the...

CHAPTER 5 NDA-24307
Page 442
Issue 1
FAULT REPAIR PROCEDURES
Initialize by loading the office data and Pro-
gram Data from hard disk using command 
“MEM_HDD.”Set SYSTEM DATA key on the TOPU to
LOAD position
Using “MEM_HDD,” load the office data and 
Program Data from the Hard Disk into the data 
memory.
Confirm the SENSE switch is set at “2” on the 
DSP (CPU).
Press RST on the DSP.
Confirm OPE lamp illuminates on each basic 
circuit card.
Insert removed control circuit cards of CPU 
No. 0 and line/trunk...