NEC Mcu 5000a Multipoint Control Unit Equipment Manual

NECA 340-414-500 Revision 2.0 Page 3 of 14
MCU 5000A Multipoint Control Unit INT-001
Figure 1:   Unit Layout of MCU 5000A
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CABLE SPACE
01 23 45 6 7
8
024 6810121416182022
24 2628 (U) 1U = 1.75 inches (44.45...

Page 4 o f 14   NECA 340 -41 4-5 00 Revisi on  2.0
INT-001   MCU 5000A Mult ipoint Con trol Unit
5.  LOOPBACK TEST 

NECA 340-4 14- 50 0  Revisio n 2.0   Page  5  of  14
MCU  5000A Multipoint Control  U nit   INT-001
Figure 2 :   MCU Loopback Points
REL AY   IP AF   MTSC  
MTSC   MTSC   M
TSC
REL AY   MTSC  
MTSC   M
TSC   M
TSC
(a)  1.5M LIF Loopback Points 

Page 6 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
Video Signal Loopback Test
5.07
The video signal Loopback test is performed through the use of the PN 
Pattern Generator/Checker function of the V SW/LSD IF unit.  The PN Pattern 
signal sent from the PN Pattern Generator returns from the loopback point set to 
make the local side Loopback and input to the PN Pattern Checker.  The PN 
Pattern Checker compares and judges the sent pattern with the input one.  When 
the...

NECA 340-414-500 Revision 2.0 Page 7 of 14
MCU 5000A Multipoint Control Unit INT-001
Diagnosis
5.11
The M CONT unit conducts the diagnosis of the hardware during the 
initial processing after power-up, and the result is indicated by the LED.   When  a 
failure has occurred during the operation, the failure condition is also indicated by 
the LED.
• ST8:lights when the battery voltage of the memory card drops or the mem-
ory card is not mounted.  When the memory card is not mounted, reset and 
restart...

Page 8 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
6.  TROUBLESHOOTING
6.01
There are two methods for troubleshooting.  One sectionalizes the failure 
according to the failure conditions (output state  of  the  video  and  audio)  and  
the  other  does  it  in accordance  with  the  LED indication of each unit.  The 
following describes the procedure of sectionalizing failures of the MCU 5000A 
through the combined use of above two methods.
A. Sectionalization in...

NECA 340-4 14- 50 0  Revisio n 2.0   Page  9  of  14
MCU  5000A Multipoint Control  U nit   INT-001
B. Sectionalization by  

Page 10 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
Table 4: Troubleshooting by LED Indication of Each Unit (1 of 2)
UNIT LED ALARM FAILURE REFERENCE NO.
1.5M
LIF
unit/
H0-INF
LIF
unitRC1
RC2REC NOS of CHI (CH5) (input off)
 LOS (out of synch)
TCP-006/TCP-008 AIS AIS of CHI (CH5) (network side fault)
RAI RAI of CHI (CH5) (remote alarm)
Normal CHI (CH5) other than the above alarms or 
normal
RC3
RC4REC NOS of CH2 (CH6) (input off)
LOS (out of synch)
AIS AIS of CH2 (CH6)...

NECA 340-414-500 Revision 2.0 Page 11 of 14
MCU 5000A Multipoint Control Unit INT-001
 
Table 4: Troubleshooting by Led Indication of Each Unit (2 of 2)
UNIT LED ALARM FAILURE REFERENCE NO.
EC H.221
MUX
unitRE16 REC H221 out of synch
TCP-009 RC15 REM ALM H221 receives A bit (REALM)
RC10 FUN ERR Function test error of MUX
RC9 MEN ERR Memory test error
PG/SIO
unitRC1 CLOS Loss of line clock input
TCP-010 RC2 SLP 3Phase slip between line clock and 
10.752 MHz clock
RC3 SLP 2Phase slip between line clock and...

Page 12 of 14 NECA 340-414-500 Revision 2.0
INT-001 MCU 5000A Multipoint Control Unit
7.  REPLACEMENT OF UNIT
7.01
When the replacement of unit is required as a result of troubleshooting, 
mount the unit correctly referring to the unit layout in Fig. 1.
7.02
Refer to TCP-017
 for the replacement of the unit.
8.  HANDLING OF MEMORY CARD
8.01
This section describes the handling of memory card mounted on the M 
CONT unit.  This memory card is of SRAM type and backed up by a lithium 
battery.
A. Replacement...