Transcript No Slide Title

Troubleshooting
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Introduction
• This section provides you with the
necessary skills to effectively
troubleshoot the DIRECTV System
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Objectives
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Test signal using a signal meter
Verify correct voltage from the IRD
Test for an open circuit
Test for a short circuit
Field test the LNB
Run a system test on the IRD
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Troubleshooting
• Identifying Symptoms
– No picture on television
– Searching for Satellite
– Missing Channels
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Troubleshooting
• System Inspection
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Animal chewed through cable
Cable jacket is damaged by weed-eater
Cable stapled or kinked
Improper ground
Improper electrical outlet
Improper Connectors
Damage to reflector or mount
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Signal Level Meter
• These 3 signal level meters are the most
common used in the field today
• The signal level meter reads the level of signal
in the line
• Advanced signal level meters like the BirdDog
can identify specific satellites
• In Line meters may have an option that allows
you to read voltage
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Quick Hit Troubleshooting
• Determine the Signal at the IRD
– Determine the defective component with SFSS
on all odd, all even or several transponders
– What is the signal level
• No signal or low signal at IRD
– Do a hard reboot
– Check the cable connections
– Read signal level at the back of the receiver
using a signal level meter
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Quick Hit Troubleshooting
• Good signal on the meter, but not on the
IRD
– Check voltage out of IRD
– Using a binding post adapter or a pre-made test
connector check the voltage, the black lead to the
shield and the red lead to the center conductor
• Use VOM
– Voltage should display as switching between 13
and 18 volts
– No voltage or voltage not switching – replace
receiver
– Voltage detected but no signal level on IRD –
replace receiver
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Quick Hit Troubleshooting
The Volt Ohm Meter
• VOMs can read AC or DC
voltage
• VOMs can read resistance in
Ohms
Ω
• VOMs are battery powered
when checking resistance
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Quick Hit Troubleshooting
The Volt Ohm Meter
• All VOMs have 2 leads or
probes
• Connecting Leads
• Reading Voltage
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Quick Hit Troubleshooting
The Signal Level Meter
– Can read voltages at the LNB loaded
• This means that the Signal Level Meter
reads the true voltage on the line with the
draw from the LNB
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Troubleshooting In Line
Components
• No Signal from ODU Cable
– Are there other receivers on the account?
• If yes, are they working?
– If they are, the problem is isolated to this
receiver and feed
– Proceed to the multiswitch or ODU;
whichever is feeding this outlet
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Troubleshooting In Line
Components
• No Signal from ODU Cable
– If you have very weak or no signal at the
port, test the other ports and see if they are
working properly
• If the other ports are providing adequate
signal but this one isn’t, replace the
multiswitch
• If all ports have low signal level check
the input signal to the multiswitch
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Troubleshooting In Line
Components
• Signal coming in from multiswitch is
low
– Common Problems
• Electrical Surge
• Corroded/Damaged “F” Connectors
• Incorrect or Damaged Cable
• Moisture Migration
• Poor Return Loss
• Failed Internal Parts
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Troubleshooting In Line
Components
• If the signal coming into the multiswitch
is low, go to the ODU and check the
output at the LNB.
– If low or no signal, look to see if there are
any obstructions blocking signal
– If there is clear line if sight attempt to
realign the ODU to peak signal
– If you can not get signal replace the LNB
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Troubleshooting In Line
Components
• Good Signal From ODU
– Test the drop to the multiswitch or the
defective receiver for an open or a
short
• The Volt Ohm Meter
– Reading Resistance
» Shorts, opens and damage
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Troubleshooting In Line
Components
• Short Circuit Test
– Disconnect cable on both ends
– Set multi-meter to ohms
– Touch one lead to center conductor and
the other to the braid.
– Meter should read 0, open or infinite
– A short will be indicated by a fluctuating
or constant resistance
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Troubleshooting In Line
Components
• Open Circuit Test
– Remove the cables from the LNB
– Short cable using 75 ohm terminator
– Set multi-meter to ohms
– Touch one lead to center conductor and
the other to the braid
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Troubleshooting In Line
Components
• Open Circuit Test (Continued)
– Meter should read 75 ohms or greater, the
longer the cable the greater the resistance
in the circuit (Approximately. 1.6 Ohms per
100 feet of RG-6
– An indication of an open circuit would read
0, open or infinite
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Troubleshooting In Line
Components
• Damaged Cable Test
– Check the resistance of a terminator which
should read approximately 75 Ohms:
• Firmly holding the black probe to the outer case and
firmly pressing the red probe to the center conductor
• Once the resistance is known, connect the
terminator to one end of the cable and read
the resistance at the other end using a
binding post adapter or an adapter you
made.
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Troubleshooting In Line
Components
• Good Signal From ODU
– Consider the Voltage drop, attenuation and
insertion loss
• Use a signal level meter to calculate cable
attenuation using a fixed scale for RG11, RG6 &
RG59
Loss estimate per 100 feet at 68º F at 1450 MHz
•RG11 = -5.29
•RG6 = -7.89 •RG59 = -9.82
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Troubleshooting In Line
Components
The Signal Level Meter
– Calculating cable attenuation at 2150 MHz
Loss estimate per 100 feet at 68º F at 2150 MHz
•RG11 = -6.60
•RG6 = -9.69 •RG59 = -12.10
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Troubleshooting In Line
Components
• Good Signal From LNB
– Calculate the signal loss between the
ODU and multiswitch
• Consider the cable loss and insertion
loss of other component
– Look for defective components
– Check each device to determine the signal
level coming in and out
– If you suspect the drop is defective test
for a short or open
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Troubleshooting In
Line Components
• In Line Devices
– The cable used for a DIRECTV installation
should always be approved RG6 coaxial.
– Signal Loss:
• Impact at 950 to 1450 MHz
– 7.89 dB per 100 feet
• Impact at 250 to 2150 MHz
– 9.69 dB per 100 feet
• Voltage drop per 100 ft at 18 volts with 300
milliamp draw
– .48 volts per 100 feet
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Troubleshooting In Line
Components
• Power Loss - dB
– Some Signal Meters on the market can
show you the dB values as well as signal
strength
– Generally you will see dB values at the ODU
around - 32dB
– The DIRECTV receivers can still show
picture at levels no less than - 60dB
– F-Connectors give you - .5dB loss per
– F-81 barrels give you - 1dB loss per
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Troubleshooting In Line
Components
• Good Signal From LNB
– Calculate the signal loss between the ODU and
multiswitch
• Consider the cable loss and insertion loss of
all other components.
– Is the loss greater than your calculation?
If so:
» Is the cable all RG6?
» Are all components rated for the
frequency spectrum you need for the
receiver
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Troubleshooting In Line
Components
• Good Signal From MultiSwitch
• If the drop feeding the multiswitch now has good signal
at that location check the output of the switch again
• If the drop feeding the multiswitch has no signal at that
location and there are no in-line components replace that
cable run
• You can run a temporary drop to confirm a cable
problem
• If there are any in line components test the input
signal and output signal of each to determine which
has failed
• Replace any defective components or cable and
reconnect the feed to the switch
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Using Test Equipment
Open Ground
Open Neutral
•The scale on the
unit enables you
to determine the
status of the
outlet
Open Hot
Hot/Ground
Reversed
Hot/Neutral
Reversed
Correct
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Summary
• Now that you have completed this
section you should be able to:
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Test signal using a signal meter
Verify correct voltage from the IRD
Test for an open circuit
Test for a short circuit
Field test the LNB
Run a system test on the IRD
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Exercise
• Hands-On
– Station #1 Verify Voltage & Signal Strength
– Station #2 Open and Short Circuits
– Station #3 Troubleshooting Wall
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