Mitel Sx 50 Dpabx Instructions Guide

							Troubleshooting Procedures and General Maintenance Information 
A 12 0034 NO TRUNK RELEASE ACK. 05/02 
Alarm Code 
Equipment Number 
Explanatory message 
Slot/Circuit (where applicable) 
The console bell sounds whenever an alarm is generated. If the bell has been muted, 
the word BELL flashes on the LCD display. The bell stops when the ALARM key is 
pressed to read the alarm message. 
lay LED is located at the right edge of the Control C 
under the cover. A flashing digit shows the number of alarms in the alarm queue. 
displayed if there are no alarms. After a power-up or reset the display can show a 
steadily lit digit. This is an alarm code. Only codes 3,4 or 5 indicate a fatal alarm which 
prevents the system from functioning. (See Table 4-4, Troubleshooting - Alarm 
Codes). 
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							Status and Alarm Indicators 
GROUNDING 
---- BRACKET 
TEST POINTS 
1-1 II III RESET SWITCH 
II III 
4 
II 
3 STATUS 
2 SWITCH 
II ---- RS-232 PORT 
J4 
(ATTENDANT CONSOLE) 
7-SEGMENT 
DISPLAY 
CARD 
EXTRACTOR 
 EDG BAR 
DD0039 
-~. - 
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							Troubleshooting Procedures and General Maintenance Information 
GROUNDING 
AC NIGHT BELL 
RESET SWITCH 
3 STATUS 
2 SWITCH 
1 
it-1 I RS-232 PORl 
II -ATTENDANT CONSOLE) 
II  7-SEGMENT 
DISPLAY 
 CARD 
EXTRACTOR 
EDG BAR 
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							SELF-DIAGNOSTIC TEST 
3.1 Volatile RAM, PROM checksum and signal processor diagnostics are performed at 
system startup. A memory or signal processor failure is indicated by displaying a fatal 
error code on the Control Card 7-segment LED. This code identifies the failing 
component type (RAM, PROM or signal processor). 
If a fatal error is detected at startup, the system does not attempt to complete the startup 
sequence, but remains in the power fail transfer mode until reset. 
3.2 Diagnostic tests are carried out as a background task while the system is running, 
unless they are disabled. Background diagnostics can be enabled or disabled in 
CDE; enabled is default. 
The diagnostics tests run cyclically, with a IO second delay before the first test is 
started. The tests may be restarted at any point in the cycle by Maintenance Function 
*32. This feature code also unbusies any equipment currently busied out. 
If the SX-50 software detects a signal processor error after startup, the signal 
processor is re-initialized and re-programmed. During this time, background 
diagnostics are disabled. If a signal processor t-e-initialization takes place during a 
diagnostics test which relies on the signal processor, any errors detected are ignored. 
See Table 4-4 for a detailed list of the ala codes and messages that diagnostics can 
generate. 
Diagnostics make no attempt to correlate test results. Maintenance personnel must 
interpret the alarms generated by diagnostics tests when troubleshooting. To a large 
extent, diagnostics test interrelated pieces of hardware, so that a failure in one area 
may cause tests of other areas to fail. As an example, if the master DX chip fails, then 
all tests relying on DX paths will fail; i.e., inter-DX, tone detection, conferencing, DTMF 
receiver, console and line/trunk diagnostics. 
3.3 Volatile RAM checkerboard test and fixed and paged PROM checksum tests are 
carried out early during system startup. No volatile RAM is used in the startup 
sequence until the volatile RAM test is successfully completed. 
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							Troubleshooting Procedures and General Maintenance Information 
RAM and PROM checksum tests are also carried out as background tasks while the 
system is running. 
Paged non-volatile RAM checksum tests (similar to PROM checksums) are made as 
part of the set of background diagnostics tests. If a write to a non-volatile RAM is made 
while it is being checksummed then the test is aborted. 
Failed memory components are only alarmed once. The alarm message (background 
diagnostics only) identifies which page of PROM, volatile or non-volatile RAM is bad, 
from which the defective memory chip can be identified. 
3.4 Tone detector diagnostics consist of checking proper reception of a single test tone 
from a tone generator looped through the main DX chip to the tone detector. The total 
received energy and the energy around the detection frequency are checked. The 
received energy must be within 20% of the known transmitted energy in both cases. 
3.5 Tone generator diagnostics consist of connecting a tone detector to the system 
DTMF tone generator for each of the DTMF digits 1,5,9,#. The tone detector is run 
twice on each digit, with centre frequency detection at each of the two frequency 
components of the DTMF digit in turn. The total received energy, and the energy 
around the detection frequency must be within 20% of the expected energy. 
3.6 Inter-DX link operation is verified by allocatin ter-DX channels which are not 
currently in use between the main DX chip and the other two DX chips. 
A data byte (changed for each test) is output from the channel under test on the master 
DX chip. This channel is looped back to connect to itself at the other DX chip. The data 
byte is then read back on the master DX chip from data memory and checked. 
If an error occurs, the test is retried once. If it fails again, an alarm report for that link 
is generated. Further channel failures on the link are not alarmed. All channels which 
fail the test remain busied-out until the SX-50 DPABX is restarted. If 70 out of the 
possible 96 channels become busied-out, the test is no longer run. 
3.7 Console diagnostics are run if the tone generator is operational and the console is in 
the idle state. The console codec is put into analog loopback mode and a test tone 
from the tone generator is routed through the codec into the tone detector. The total 
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							Self-Diagnostic Tests 
received energy, and the energy around the test tone frequency must both be within 
20% of the known transmitted test tone energy. A console loopback error is 
generated if the console fails its loopback test. 
3.8 Line/trunk diagnostics are run if the tone detector is operational. Line and trunk cards 
are scanned for circuits in the idle state. The codec for each idle circuit is placed into 
analog loopback mode and a test tone from the tone generator is routed through the 
codec into the tone detector. The total received energy, and the energy around the 
test tone frequency must both lie within 20% of the known transmitted test tone 
energy. 
Lines and trunks which fail the loopback tests cause an alarm. Line or trunk circuits that 
have failed the loopback test are not retested until diagnostics are restarted. Failed 
trunks are busied-out. 
3.9 Conferencing diagnostics are run if the tone detector is operational. A high amplitude 
tone is sent through the first of the three conference input channels, a low amplitude 
tone through the second channel, and silence through the third channel. The 
diagnostics tone detector is used to ensure that the second loudest and quiet output 
channels receive the high amplitude tone, and the loudest channel receives the low 
amplitude tone. If a 3-party conference test fails, an alarm is generated, and the 
conference circuit is busied-out. 
3.10 The diagnostics tone generator is use o route each of the 12 DTMF tone pairs 
(0-9,*,#) through each of the five DTMF ‘receivers via the master DX chip. Correct 
detection of each digit is verified. Each DTMF receiver is tested in turn, provided it is 
not being used for call processing. 
If a failure is detected, the test is retried after 1 second. If the test fails again, the DTMF 
Receiver is suspect. However, the test is repeated on another DTMF Receiver to verify 
that tones are reaching the receivers. If this second receiver passes, the first receiver 
is busied-out and an alarm is generated; otherwise the failure is ignored. If a second 
receiver is not available, the first receiver is busied-out and an alarm is generated. 
DTMF receivers are not tested if they are currently allocated by call processing, 
however all receivers which have not been busied-out will eventually be tested, even 
if there is some delay before a period of sufficiently quiet system activity such as 
nighttime. There is a maximum number of DTMF receivers that diagnostics are allowed 
to busy out. 
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							Troubleshooting Procedures and General Maintenance Information 
The early line split hardware is also tested. If the test fails, an alarm is generated to warn 
that early line split hardware is not functioning correctly; the DTMF receiver is not 
busied-out. 
ling 
3.11 The integrity of the system scheduling queues is checked by ensuring that each 
slot-based device which ‘exists’ (has been recognized by the system) is on a 
scheduling queue. The converse is also checked; i.e., that no devices are scheduled 
which have not been recognized by the system. 
If a fault is detected then an alarm identifying the offending device is sent to the console. 
The exception to this is if data load is active, in which case the device will have been 
purposefully removed from the scheduling queues to reduce CPU load. Any alarms 
generated by this test indicate a serious system malfunction. 
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							TROUBIISHOOTNG 
PROCEDURES 
This Part presents procedures to help the field service engineer/installer analyze and 
troubleshoot problems based on the symptoms and any alarm codes that may have 
been generated. 
4.1 Handle circuit cards by their edges only and wear a ground strap properly connected 
to the card frame. 
nfir 
4.2 If a card has been replaced and the problem has been solved, the original card 
should be retried during a low traffic period to confirm that it was at fault. 
4.3 Card repair tags should always be completed, giving as much detail as possible 
about the symptoms of the problem. See Appendix C for a description of the Mite1 
Repair Tag. The system Trouble Log should be filled out in detail and kept on-site. 
4.4 When replacing a card, ensure the grounding post at the lower rear edge of the card 
engages the Energy Dumping Ground bar through the hole provided in the Control 
Card. 
4.5 If the system is completely inoperative, go to Table 4-l. Otherwise, begin at 
Table 4-3, Information Collection and Preliminary Checks. From there, proceed to 
Table 2-1, Troubleshooting -Alarm Codes if there are alarms raised, or to one of the 
equipment troubleshooting charts to 
work from symptoms. 
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							Troubleshooting Procedures and General Maintenance Information 
Follow the procedures one line at a time until the problem is solved. Generally, each 
step covers a less likely and more serious cause for the problem. For example, 
procedures call for a check of the wiring before they call for the replacement of a card. 
No lights or display. 
Check power supply fuses. (Six on left side,one near 
switch). 
Ensure that power switch is ON and is lit. 
Ensure the power cord is firmly seated at both ends. 
Check power at outlet. 
Check power at MCC test points. 
Refer to Table 2-1, Troubleshooting -Alarm Codes.  Control Card Status LED shows steady 
number other than 0 or 8. 
c Module connector. 
Note: Note: All fuses have 250 Volt rating. 
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							Troubleshooting Procedures 
Table 4-3 l~~or~atio~ Collection a 
e Do all users experience this problem? 
0 Is the problem continuous or intermittent? 
date: AUG-25 
Night 
* Static easily generated 
e System located near heat, photocopier 
* Seating of cable connectors 
e Seating of cards 
0 Seating of Generic Module connector 
* Seating of Console connector 
* Cross-connect wiring 
er cover near 
bottom right of card) reads 0 
e Off-hook stations receive dial tone 
* The clock can be set to the correct time 
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