Nautel VS2.5 Programming manual

VS2.5 Transmitter
Troubleshooting Manual
Document:NHB-VS2.5-TRB
Issue: 11.0 2019-05-10
Status: Standard

Nautel Limited
10089 Peggy’s Cove Road
Hackett’s Cove, NS Canada B3Z 3J4
Phone: [phone] or
Toll Free: +1.877.6NAUTEL (6628835) (Canada & USA only)
Fax: [phone]
Nautel Inc.
201 Target Industrial Circle
Bangor, Maine USA 04401
Phone: [phone]
Fax: [phone]
Customer Service (24 hour support)
+1.877.628.8353 (Canada & USA only)
+1.902.823.5100 (International)
Email: [email protected]
Web: www.nautel.com
The comparisons and other information provided in this
document have been prepared in good faith based on publicly
available information. The reader is encouraged to consult the
respective manufacturer's most recent published data for
verification.
© Copyright 2019 NAUTEL. All rights reserved.

VS2.5 Troubleshooting Manual Table of contents
Page v
Contents
Release control record vii
Responding to alarms 1-1
Corrective maintenance 1-1
Electrostatic protection 1-3
Identifying and troubleshooting an alarm 1-4
Troubleshooting tips 1-30
Operating with defective PAs or cooling fans 1-31
Replacing a suspect PWB, power supply or fan 1-32
PA PWB replacement 1-34
Pre-amp/IPA PWB replacement 1-37
Power Supply Module Replacement 1-40
+48 V Power Supply Replacement 1-41
Cooling fan replacement - fans 3 (B3) through 7 (B7) 1-42
Cooling fan replacement - fans 1 (B1) and 2 (B2) 1-44
Exciter/Control PWB Replacement 1-46
PS Distribution PWB Replacement 1-49
Combiner Interface PWB Replacement 1-50
Detailed Circuit Descriptions 2-1
Exciter/control PWB (NAPE87B) 2-1
PS distribution PWB (NAPS53) 2-2
Pre-amp/IPA PWB (NAPA28B) 2-3
Power amplifier PWB (NAPA31C) 2-4
Parts Lists 3-1
Parts information 3-1
Family tree 3-1

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How to locate information about a specific part 3-1
Column content 3-2
Common abbreviations/acronyms 3-3
Wiring/connector lists 4-1
Wiring lists provided 4-1
Wiring lists not provided 4-1
Connector mating information 4-1
Wire colours 4-1
Printed wiring board patterns 4-1
Reading Electrical Schematics 5-1
Component values 5-1
Graphic symbols 5-1
Logic symbols 5-1
Reference designations 5-1
Unique symbols 5-2
Identifying schematic diagrams 5-2
Structure of schematics 5-3
Locating schematic diagram(s) for a functional block 5-3
Locating a part or assembly on a schematic 5-4
Mechanical Drawings 6-1
Identifying mechanical drawings 6-1
Content of mechanical drawings 6-1
Locating a part or assembly on a mechanical drawing 6-1
List of terms 7-1

VS2.5 Troubleshooting Manual
Issue 11.0 2019-05-10 Page vii
Release control record
Issue Date Reason
11.0 2019-05-10 Supports hardware NARF66I/04 and NARF66I/05.
Supports software version VS SW 5.2 and higher.

VS2.5 Troubleshooting Manual
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VS2.5 Troubleshooting Manual Responding to alarms
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Section 1: Responding to alarms
This section provides instructions you need when performing troubleshooting on the VS2.5
transmitter. This section includes the following topics:
•Corrective maintenance
•Electrostatic protection - see page 1-3
•Identifying and troubleshooting an alarm - see page 1-4
•Troubleshooting tips - see page 1-30
–AUI lockup - see page 1-30
•Operating with defective PAs or cooling fans - see page 1-31
•Replacing a suspect PWB, power supply or fan - see page 1-32
If none of the procedures and alarms described in this section address your problem, contact
Nautel for assistance. See “Technical support” on page ix.
Corrective maintenance
Corrective maintenance procedures consist of identifying and correcting defects or deficiencies
that arise during transmitter operation. Local and/or remote alarm signals are generated when
a malfunction occurs. If an alarm condition is caused by a malfunction in the RF power stage,
the transmitter may maintain operation at a reduced RF output level. The nature of the fault –
and station policy – will dictate whether an immediate maintenance response is necessary.
Fault analysis and rectification may be conducted from three different levels, with a different
technical competence level required for each: on-air troubleshooting, remote or local, and off-
air troubleshooting.
CAUTION:
The transmitter contains many solid state devices that may be damaged if subjected
to excessive heat or high voltage transients. Every effort must be taken to ensure that
circuits are not overdriven or disconnected from their loads while turned on.

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On-air troubleshooting
On-air troubleshooting can be performed from a remote location, or locally at the transmitter
site.
Remote troubleshooting
Remote on-air troubleshooting consists of monitoring the transmitter's radiated signal using an
on-air monitor or via a LAN connection, and observing the status of each remote fault alarm
indicator. Information obtained from these sources should enable an operator to decide
whether an alarm response may be deferred to a more convenient time, an immediate
corrective action must be taken, or if a standby transmitter must be enabled (if one is
available). It is recommended that the significance of remote indications, and the appropriate
responses, be incorporated into a station's standard operating procedures. Refer to “Identifying
and troubleshooting an alarm” on page 1-4 to determine the remedial action for a given fault.
Local troubleshooting
Local on-air troubleshooting consists of monitoring the transmitter's integral meters and fault
alarm indicators. Analysis of this data will normally identify the type of fault, and in most
cases will determine what corrective action must be taken. Refer to “Identifying and
troubleshooting an alarm” on page 1-4 to determine the remedial action for a given fault.
The power amplifier stage contains an integral modular reserve (IMR) feature. This feature
permits the transmitter to operate at a reduced RF output level when a malfunction occurs in
one of its power modules. Station operating procedures will dictate whether a reduced RF
output level is acceptable. When a reduced RF output level can be tolerated, replacement of the
defective RF components may be deferred to a convenient time.
Off-air troubleshooting
Off-air troubleshooting must be performed when routine on-air calibration adjustments will
not restore operation.
It is recommended that the transmitter’s output be connected to a precision 50 resistive
dummy load (rated for at least the maximum transmitter power rating of 2500 W) before
starting off-air troubleshooting procedures. If an appropriate dummy load is not available,
troubleshooting for a majority of faults can be performed with the RF power stage turned off.
The transmitter may remain connected to its antenna system for these procedures.
CAUTION:
Reduce the RF output level to a minimal value when troubleshooting faults in the
transmitter. This is particularly important when the transmitter’s cover is removed -
where possible overheating could occur - or when the transmitter is connected to the
antenna system.

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Electrostatic protection
The transmitter's assemblies contain semiconductor devices that are susceptible to damage
from electrostatic discharge. The following precautions must be observed when handling an
assembly which contains these devices.
Electrical discharging of personnel
Personnel should be electrically discharged by a suitable grounding system (e.g., anti-static
mats, grounding straps) when removing an assembly from the transmitter, and while handling
the assembly for maintenance procedures.
Handling/Storage
An assembly should be placed in an anti-static bag when it is not installed in a host transmitter,
or when it is not undergoing maintenance. Electronic components should be stored in anti-
static materials.
Tools/Test equipment
Testing and maintenance equipment – including soldering and unsoldering tools – should be
suitable (i.e., grounded tip) for contact with static sensitive semiconductor devices.
Stress current protection
Every precaution should be taken to ensure the static sensitive semiconductor devices are
protected from unnecessary stress current. This is achieved by ensuring that current is not
flowing when an electrical connection is broken, and that voltages are not present on external
control/monitoring circuits when they are connected.
CAUTION:
Electrostatic energy is produced when two insulating materials are rubbed
together. A person wearing rubber-soled shoes, walking across a nylon carpet or a
waxed floor, can generate an extremely large electrostatic charge. This effect is
magnified during periods of low humidity. Semiconductor devices such as
integrated circuits, field-effect transistors, thyristors and Schottky diodes may be
damaged by this high voltage unless adequate precautions are taken.

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Identifying and troubleshooting an alarm
You can identify an alarm locally by viewing the front panel (see “Front panel alarm checks”)
or remotely by viewing the AUI’s Transmitter Status page (see “AUI Transmitter status page
checks” on page 1-7).
Front panel alarm checks
There two ways to check for alarms on the front panel:
•Alarm/status LEDs
•View alarms screen - see page 1-5
Alarm/status LEDs
There are four LEDs on the left-hand side of the LCD display that provide information about
the operational status of the transmitter -
Exciter , Power Amplifier , Output Network and Power
Supply
(see Figure 1.1). The LEDs can glow green, amber or red. Typically, green indicates
normal operation, amber indicates a warning, and red indicates a fault or error.
Figure 1.1: Alarm/Status LEDs
When an LED is:
• green - transmitter is on, with no known faults.
• amber - a fault is present that may cause a reduction in RF power, but the transmitter is
still producing RF power.
• red - a fault is present and the transmitter is not producing RF power.
When a fault is present, the transmitter may still produce an RF output. In this case, or if the
transmitter has shut down, you should schedule and commence more in-depth fault diagnosis.
See “View alarms screen” on page 1-5.
Exciter
Power Amplifier
Output Network
Power Supply

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View alarms screen
If an alarm exists and is currently being recognized by the transmitter system, it is displayed in
the View Alarms screen ( Main Menu -> View Status -> View Alarms ) of the front panel Display
(see Figure 1.2).
Figure 1.2: View Alarms Screen
Table 1.1 on page 1-9 contains a column for most alarms that can occur, sorted alpha-
numerically. The
Description and Troubleshooting Action column provides a brief description
of the alarm, troubleshooting tips and a cross-reference to more troubleshooting, if applicable.
1. Scroll through the View Alarms screen to view the active faults.
2. Attempt to clear any latching alarms by pressing the checkmark button in the
Main
Menu -> Reset Alarms
screen. If the alarm persists, it will not clear from the display.
3. Locate the alarm name in Table 1.1 on page 1-9 to determine the cause of the alarm and
perform any recommended procedures in the Description and Troubleshooting Action
column. This may also lead to replacing a suspect PWB, power supply or fan, as
detailed in “Replacing a suspect PWB, power supply or fan” on page 1-32.
NOTE:
Before undertaking any troubleshooting, record all meter readings and note if any
other alarms are displayed on the View Alarms screen . Record all alarms.
NOTE:
Table 1.1 on page 1-9 contains a column for most Alarms that can occur, sorted
alphanumerically for each sub-system, including both the names displayed on the
AUI and, if different, the front panel UI (in parentheses).
The Description and Troubleshooting Action column provides a description of the
alarm, troubleshooting tips and a link to detailed troubleshooting, as applicable.

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4. Refer also to Table 1.2 on page 1-27 for Summary alarms that can occur - when
properly configured - as remotely monitored outputs.
5. If troubleshooting and subsequent replacement of a suspect PWB or module causes the
alarm to disappear from the View Alarms screen, the alarm has been successfully
cleared. If the fault condition does not clear, contact Nautel.
NOTE:
Table 1.2 lists the Summary alarms that can be configured for remote
monitoring through the front panel UI’s Main Menu -> User Settings ->
Remote I/O -> Remote Outputs screen (see the “Operating the Transmitter”
section of the Operations & Maintenance Manual for configuration details). Each
Summary alarm can be triggered by any one alarm in a specific sub-set, as shown
in Table 1.2. The Description and Trigger Alarms column of Table 1.2 provides
a brief description of the summary alarm and a list of the triggering alarms. To
determine the root cause(s) of a Summary Alarm, check the front panel UI for an
offending trigger alarm and refer to its troubleshooting information in Table 1.1
on page 1-9 for more details.

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AUI Transmitter status page checks
If an alarm exists and is being recognized by the transmitter (i.e., the Status button at the
bottom of the AUI display will be red), it is displayed on the transmitter status page (see
Figure 1.3). The Device name indicates the sub-system origin of the alarm. The sub-systems
that can be displayed are:
– Controller: All alarms in this sub-system apply to the controller.
– Exciter: All alarms in this sub-system apply to the exciter.
Figure 1.3: Transmitter Status Page
1. Click the Status button to go to the Transmitter Status page (see Figure 1.3). View the
list of active faults. Alarms are listed by their origin ( Device column), then by name
( Alarm column), and then by severity ( Level column) [single orange ! indicates low
severity (RF output not affected); single red ! indicates medium severity (RF output is
reduced); two red ! indicates high severity (RF output is inhibited)].
2. Attempt to clear any latching alarms by pressing the Reset button on the bottom
banner of the page. If the alarm persists, it will not be cleared from the display.

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3. Locate the alarm name in Table 1.1 on page 1-9 to determine the cause of the alarm and
perform any recommended procedures in the Description and Troubleshooting Action
column. This may also lead to replacing a suspect PWB, power supply or fan, as
detailed in “Replacing a suspect PWB, power supply or fan” on page 1-32.
4. Refer also to Table 1.2 on page 1-27 for Summary alarms that can occur - when
properly configured - as remotely monitored outputs.
5. If troubleshooting and subsequent replacement of a suspect PWB or module causes the
alarm to disappear from the Transmitter Status page, the alarm has been successfully
cleared. If the fault condition does not clear, contact Nautel.
NOTE:
Before undertaking any troubleshooting, record all meter readings and note if any
other alarms are displayed on the View Alarms page . Record all alarms. Use the
remote AUI’s Critical Parameters page (Menu -> User Settings) to Capture Meters
and Capture Alarms, which copies meter readings and active alarms into a
spreadsheet for future reference.
NOTE:
Table 1.1 on page 1-9 contains a column for most
Alarms that can occur, sorted
alphanumerically for each sub-system, including both the names displayed on the
AUI and, if different, the front panel UI (in parentheses).
The
Description and Troubleshooting Action column provides a description of the
alarm, troubleshooting tips and a link to detailed troubleshooting, as applicable.
NOTE:
Table 1.2 lists the Summary alarms that can be configured for remote
monitoring through the remote AUI’s Menu ->Remote I/O -> Remote
Outputs page (see the “Operating the Transmitter” section of the Operations &
Maintenance Manual for configuration details). Each Summary alarm can be
triggered by any one alarm in a specific sub-set, as shown in Table 1.2. The
Description and Trigger Alarms column of Table 1.2 provides a brief description
of the summary alarm and a list of the triggering alarms. To determine the root
cause(s) of a Summary Alarm, check the remote AUI for an offending trigger
alarm and refer to its troubleshooting information in Table 1.1 on page 1-9 for
more details.

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Table 1.1: Troubleshooting Alarms
Alarm Name
AUI and
(Front Panel)
Front Panel
LED (color) Description and Troubleshooting Action
+1.2V Supply
Fail
(+1.2V Fail)
PS (red) This alarm occurs if the +1.2 V supply on the exciter/control PWB
(A1) is outside of its acceptable voltage range (between +1.1 V
and +1.3 V). The VS2.5 takes no action on this alarm. Check for a
+5V Supply Fail alarm: If present, follow the associated
troubleshooting procedure. If not present, use a digital multimeter
to measure between TP3 (+1.2 V) and TP4 (ground) of the
exciter/control PWB. If the measured value is within the
acceptable range, suspect the sampling circuitry on the exciter/
control PWB (A1). If not, use a digital multimeter to measure
between TP5 and TP4 (ground). The measured voltage should be
between +4.5 V and +5.5 V. If the measured voltage is within the
acceptable range, the power supply circuitry on the exciter/control
PWB has failed. Replace the exciter/control PWB (see “Exciter/
Control PWB Replacement” on page 1-46). If not, check ribbon
cable W4 for damage, and verify connectors W4P1 and W4P2 are
properly seated in A1J11 and A2J6 respectively. If there are no
visible problems with the ribbon cable, contact Nautel for further
support.
+1.8V Supply
Fail
(+1.8V Fail)
PS (red) This alarm occurs if the +1.8 V supply on the exciter/control PWB
(A1) is outside of its acceptable voltage range (between +1.6 V
and +2.0 V). The VS2.5 takes no action on this alarm. Check for a
+3.3V Supply Fail alarm: If present, follow the associated
troubleshooting procedure. If not present, use a digital multimeter
to measure between TP2 and TP4 of the exciter/control PWB. If
the measured value is within the acceptable range, suspect the
sampling circuitry on the exciter/control PWB. If not, the power
supply circuitry has failed on the exciter/control PWB. If
necessary, replace the exciter/control PWB (see “Exciter/Control
PWB Replacement” on page 1-46).

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+15V Supply
Fail
(+15V Fail)
PS (amber) This alarm occurs if the +15 V supply from the PS distribution
PWB (A2) is outside of its acceptable voltage range (between
+13.5 V and +16.5 V). The VS2.5 takes no action on this alarm.
Check for a +48V Supply Fail alarm: If present, follow the
associated troubleshooting procedure. If not present, use a digital
multimeter to measure between TP1 (+15 V) and TP3 (ground) of
the PS distribution PWB. If the measured value is not within the
acceptable range, the power supply circuitry on the PS distribution
PWB has likely failed. If the measured value is within the
acceptable range, check ribbon cable W2 for damage and that
connectors W2P1 and W2P2 are properly seated in A1J12 and
A2J7 respectively. If there are no visible problems with the ribbon
cable, suspect the sampling circuitry on the PS distribution PWB.
If necessary, replace the PS distribution PWB (see “PS
Distribution PWB Replacement” on page 1-49). If the alarm
persists after replacing the PS distribution PWB, suspect the
exciter/control PWB (A1).
-15V Supply
Fail
(-15V Fail)
PS (amber) This alarm occurs if the -15 V supply on exciter/control PWB (A1)
is outside of its acceptable voltage range (between -13.5 V and
-16.5 V). The VS2.5 takes no action on this alarm. Check for a
+15V Supply Fail alarm: If present, follow the associated
troubleshooting procedure. If not present, use a digital multimeter
to measure between TP11 and TP7 (ground) of the exciter/control
PWB. If the measured value is within the acceptable range,
suspect the sampling circuitry on the exciter/control PWB. If not,
use a digital multimeter to measure between TP23 and TP4
(ground). The measured voltage should be between +13.5 V and
+16.5 V. If the measured voltage is within the acceptable range,
the power supply circuitry on the exciter/control PWB has failed.
Replace the exciter/control PWB (see “Exciter/Control PWB
Replacement” on page 1-46). If not, check ribbon cable W4 for
damage and that connectors W4P1 and W4P2 are properly
seated in A1J11 and A2J6 respectively. If there are no visible
problems with the ribbon cable, contact Nautel for further support.
Alarm Name
AUI and
(Front Panel)
Front Panel
LED (color) Description and Troubleshooting Action

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+3.3V Supply
Fail
(+3.3V Fail)
PS (red) This alarm occurs if the +3.3 V supply on the exciter/control PWB
(A1) is outside of its acceptable voltage range (between +3.0 V
and +3.6 V). The VS2.5 takes no action on this alarm. Check for a
+5V Supply Fail alarm: If present, follow the associated
troubleshooting procedure. If not present, use a digital multimeter
to measure between TP1 (+3.3 V) and TP4 (ground) of the
exciter/control PWB. If the measured value is within the
acceptable range, suspect the sampling circuitry on the exciter/
control PWB. If not, use a digital multimeter to measure between
TP5 and TP4 (ground). The measured voltage should be between
+4.5 V and +5.5 V. If the measured voltage is within the
acceptable range, the power supply circuitry on the exciter/control
PWB has failed. Replace the exciter/control PWB (see “Exciter/
Control PWB Replacement” on page 1-46). If not, check ribbon
cable W4 for damage and that connectors W4P1 and W4P2 are
properly seated in A1J11 and A2J6 respectively. If there are no
visible problems with the ribbon cable, contact Nautel for further
support.
+5V Supply
Fail
(+5V Fail)
PS (red) This alarm occurs if the +5V-B supply from the PS distribution
PWB (A2) is outside of its acceptable voltage range (between
+4.5 and +5.5 V). The VS2.5 takes no action on this alarm. Check
for +48V Supply Fail alarm: If present, follow the associated
troubleshooting procedure. If not present, use a digital multimeter
to measure between TP20 (+5V-B) and TP28 (ground) of the PS
distribution PWB. If the measured value is not within the
acceptable range, the power supply circuitry on the PS distribution
PWB has failed. If the measured value is within the acceptable
range, check ribbon cable W2 for damage and that W2P1 and
W2P2 are properly seated in A1J12 and A2J7 respectively. If
there are no visible problems with the ribbon cable,
suspect the sampling circuitry on the PS distribution PWB.
Replace the PS distribution PWB (see “PS Distribution PWB
Replacement” on page 1-49). If the alarm persists after replacing
the PS distribution PWB, suspect the exciter/control PWB (A1).
Alarm Name
AUI and
(Front Panel)
Front Panel
LED (color) Description and Troubleshooting Action

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All Power
Amplifiers
Inactive
(All PAs
Inactive)
PA (red) This alarm indicates that all of the PAs in the system or all of the
power supply modules in the system have failed simultaneously;
therefore PA failure alarms or power supply module related
alarms should also be present. If there are power supply module
related alarms present, or an IPA Output Low alarm, follow the
associated troubleshooting procedure. If there are no power
supply module related alarms, with RF turned on, use a digital
multimeter to measure the voltage between pad V and pad W on
any PA. If the voltage does not fall within an acceptable range
(between 2.3 V and 3 V), suspect the exciter/control PWB (A1). If
the voltage does fall in the acceptable range, perform the “PA
resistance checks” on page 1-35.If there is no problem found with
any of the PAs, or the alarm still persists after replacing all of the
damaged PAs, suspect the PS distribution PWB (A2).
Analog Left
Audio Low
(Anlg Left Aud
Low)
Exciter (amber) This alarm indicates the analog left audio input level is too low or
is not applied. The VS2.5 takes no action on this alarm.
Analog Right
Audio Low
(Anlg Right
Aud Low)
Exciter (amber) This alarm indicates the analog right audio input level is too low or
is not applied. The VS2.5 takes no action on this alarm.
Audio Loss Exciter (red) This alarm, enabled by the user, indicates that the exciter’s audio
modulation level is below the level specified in the mod loss
settings of the active preset [see page 2-72 (remote AUI) or “Mod
Loss” on page 2-93 (front panel UI)] of the Operations and
Maintenance Manuals to enable/disable this alarm and to
configure the resulting action). Depending on the setting, this
alarm could trigger a preset change, inhibit RF or have no effect
(alarm only). Check the appropriate program input(s) and the mod
loss setting for the preset.
Audio
Processor
Offline
Exciter (amber) This alarm occurs if the exciter is configured to include an Orban
Inside audio processor, but it is not communicating with the
processor on the internal serial bus. Check all connections to the
Orban Inside audio processor card.
Audio
Processor
Output Fail
Exciter (amber) This alarm occurs if the exciter is configured to include an Orban
Inside audio processor, but it is not detecting audio from the
processor. Check all connections to the Orban Inside audio
processor card.
Alarm Name
AUI and
(Front Panel)
Front Panel
LED (color) Description and Troubleshooting Action