Chapter 7
Basic Troubleshooting
and
Repair Procedures
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Overview
• Tools Needed
• Circuit Troubleshooting
• Electrical Interference
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Tools Needed
•
•
•
•
•
Multimeters
Wiring Tools
Miscellaneous Tools
Do-It-Yourself Test Tools
Commercial Testers
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Multimeter
• Required features in a boat’s multimeter
 Measure up to 50 VDC
• DC voltages either 6, 12 and sometimes 24
 Measure up to 250 VAC
• AC voltages either 120 or 240
 Measure resistance or continuity
• Audible continuity checker is desirable
• Desirable features
 Measure AC and DC current up to 10 amps
 Entry level measure current to approx. 250 mA
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Analog Multimeter
• Advantage - Low cost
• Disadvantages
 Difficult to read measurement value
 Have to start at max value and work way down
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Digital Multimeter
• Advantages
 Easy to read measurement value
 More accurate readout
• Disadvantages
 Have to start at max value and work way
down
 Cost
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Auto-Ranging Multimeter
• Advantage
 Only have to select function (not range)
• DC voltage, DC current, AC voltage or resistance
• Disadvantage - cost
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Wiring Tools
• Wire Cutter – Diagonal Cutter
 5 or 6” overall
 Plastic cushion grip
• Wire Stripper
 Don’t use knife
 Are dedicated tools
 Most used – Combination Cut/Strip/Crimp Tool
• Not to be used as crimp tool
• Wire cutters at tip not effective
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Wire Cutters / Wire Strippers
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Wiring Tools - 2
• Ratcheting crimp tool required by ABYC
 Covered in Chapter 2
 Expensive compared to combination tool
• Soldering gun
 Normally boat wiring is NOT soldered
• Done with crimp on terminals and butt spices
 Required for some coax connectors
 Recommend dual 100/140 watt
 With appropriate tip will cut lines and fuse ends
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Crimp Tool / Soldering Gun
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Miscellaneous Tools
• Pliers
 To hold objects
• Not a substitute for a wrench
 Types
• Slip joint
• Needle nose
• 5” or 6” overall with plastic cushioned grips
• Wrench (for electrical work)
 Adjustable 6”
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Pliers / Adjustable Wrench
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Screwdrivers
• Blade
 3/16” blade with 4” shaft
 1/4” blade with 4” shaft
• Phillips
 #1 with 4” shaft
 #2 with 4” shaft
• Small
 1/8” blade with approx. 2” shaft
 #0 Phillips with approx. 2” shaft
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Screwdrivers
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Circuit Trouble-Shooting
•
•
•
•
•
•
Batteries
Alternators
Battery Chargers
Boat Lighting System
Boat DC Electronic Systems
Boat AC Circuits
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Battery Testing
•
•
•
•
Hydrometer
Open-Circuit Voltage
Load Test
Three-Minute Charge
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Hydrometer
• Hydrometer – best tester of flooded-cell
 Measures Specific Gravity
 Chapter 3, Table 5
Specific Gravity
100
% charge
1.265
75
% charge
1.225
50
% charge
1.190
25
% charge
1.155
Discharged
1.120
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Open-Circuit Voltage
• For Maintenance Free, Gel & AGM batteries
 When you can’t use a hydrometer
• Battery should rest for 24 hours, or
discharge with a large light bulb for a few
minutes
• Chapter 3, Table 5
Voltage
Flooded
Gel
AGM
100
% charge
12.65
12.90
12.85
75
% charge
12.4
12.65
12.6
50
% charge
12.2
12.35
12.3
25
% charge
12.0
12.0
12.0
Discharged
11.8
11.8
11.8
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Specific Gravity & Voltages
100 % charge
75 % charge
50 % charge
25 % charge
Discharged
Specific Gravity
(Flooded Cell @ 80 F)
Flooded Cell
Voltage
Gelled Cell
Voltage
AGM
Voltage
1.265
1.225
1.190
1.155
1.120
12.6 to 12.7
12.4
12.2
12.0
11.8
12.85 to 12.95
12.65
12.35
12.0
11.8
12.8 to 12.9
12.6
12.3
12.0
11.8
14.2 to 14.4
14.2 to 14.4
13.2 to 13.6
15.0 to 16.0
13.8 to 14.1
13.5 to 13.8
13.2 to 13.5
Do NOT Equalize
14.4 to 14.6
14.1 to 14.4
13.2 to 13.5
Do NOT Equalize
Charging voltage @ 80º F
Bulk
Acceptance
Float
Equilization
-
Chapter 3 Table 3-5
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Load Test
• Hydrometer and open-circuit voltage do not
indicate ability to provide current under
load
• Prevent engine from starting
 Operate starter motor for approx 15 sec
 Monitor battery voltage after 5 sec
• If voltage is over 10.5 VDC – Good Battery
• If voltage is under 10.5 VDC – Bad Battery
 Replace battery
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Three-Minute Charge Test
• Actually takes six (6) minutes
• Charge battery at 40A for six minutes
• Measure voltage (at battery) with charger on
• If voltage under 15.5 VDC – Battery is good
• If voltage is over 15.5 VDC – Battery is bad
 Not accepting charge
 Is sulfated
 Replace battery
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Alternator Testing
• Drive Belt
• Quick Test
• Alternator Electrical Connections
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Drive Belt & Quick Test
• Drive belt
 Loose belt if “squealing” when engine started
 Belt depression when pressed at midpoint
• Normal (correct tightness) is only 3/8” to ½”
• Over ½” is too loose, tighten belt
• Quick test with engine & battery charger off
 Measure (battery) voltage at alternator
 Start engine and measure voltage at alternator
• Alternator working if voltage increases
• Alternator not working if voltage constant
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Alternator Electrical Connections
To check wiring between alternator & battery
• First discharge battery for five minutes
• Then start engine & check for high resistance
connection between alternator & battery
• Voltage drop over 0.5 VDC needs to be fixed;
or over 1.0 VDC if there are charging diodes
 Check both positive and negative circuit
 Clean and tighten the bad connection
 If you find a bad wire, replace it
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Battery Charger Testing
• Alternator vs Battery Charger
• Quick Test
• Troubleshooting
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Alternator vs Charger & Quick Test
• Alternator vs Battery Charger
 Batteries charged by alternator
 Batteries not charged by battery charger
• Defective battery charger; see Troubleshooting
• Quick test with engine & charger off
 Measure (battery) voltage at battery charger
 Turn on battery charger and measure voltage
• Battery charger working if voltage increases
• Battery charger not working if voltage constant
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Troubleshooting
• If Charger not working, check the AC input
 Troubleshoot like AC Circuit, covered later
• If there is AC input, check for a blown fuse
 Replace blown fuse ONCE
 If fuse blows a 2nd time
• Disconnect wire going to battery and
install another fuse, then turn charger on
• If fuse blows again, have defective charger
• If fuse does NOT blow, measure DC voltage
– Should be between 13 and 16 VDC
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Troubleshooting - 2
• Turn Charger “Off”
• Disconnect charger positive wire at battery
 Tape it to prevent wire shorting to ground
• Reconnect positive wire at charger
• Turn “On”, if fuse blows have short in wire
• If fuse does not blow, may have high resistance
connection between charger and battery
 Troubleshoot wiring like you would for alternator
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Boat Lighting System
• Boat light inoperative
 First replace bulb with known good bulb
 Alternate test of suspect bulb
• Check continuity of filament
–Good bulb will have continuity
or low resistance
–Bad bulb will indicate no continuity
or infinite resistance
 If good bulb does not work
• Need to troubleshoot lighting circuit
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Lighting Troubleshooting
• Need a logical sequence
• First check circuit breakers and switches
• Then isolate to battery to power panel
or
• Power panel to light
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Boat Light Inoperative
Replace / Check
Bulb
A
Light
Working
?
Yes
Stop
NO
Power
to Panel
?
NO
Troubleshoot
Panel to Light
NO
Turn
Battery
Switch On
A
Troubleshoot
Battery to Panel
Yes
DC
Main On
?
Yes
Battery
Switch On
?
Yes
NO
Turn DC
Main On
A
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Battery to Power Panel
No DC at battery side of DC main breaker
• Check/replace large fuse at battery
 Use multimeter
• Check/clean/tighten wiring
 Battery to battery fuse
 Batter fuse to power panel
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Power Panel to Light
Have DC at load side of branch circuit breaker
• Check/clean/tighten wiring at branch breaker
• Check/clean corrosion at light socket
 Use CRC QD Electronic Cleaner or equivalent
• Check/replace in-line fuse near light
• Check/replace switch in light
• Check wiring with temporary wires from
branch circuit breaker to light fixture
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Boat DC Electronic Systems
• 90% of equipment problems is lack of DC
or bad corroded cable connections
• First check for power to equipment
 If there is power
• Check for blown fuse
• If fuse is good, there is an equipment problem
• Then check/clean cable connections
 Use CRC QD Electronic Cleaner or equivalent
• Lastly troubleshoot like a lighting system
 Previously covered
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Boat AC Circuits
• Testing
• Troubleshooting
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Testing AC Circuits
• Shore power polarity
 Verify correct with Reverse Polarity Indicator
• Outlets
 When first installed and once a year
 Verify with AC Outlet Tester
• GFCI outlets
 When first installed and once a year
 Insert AC Outlet Tester
• Press “Test” – tester lights should go “Off”
• Press “Reset” – tester lights should go “On”
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Testing Hard Wired Appliances
• Turn on appropriate branch circuit breaker
and
• Appliance “On” switch
• Appliance should work
or
• Expose the AC terminal strip
 Use multimeter
 Check for AC voltage and polarity
• If have AC input and won’t work = Defective
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Troubleshooting AC Circuits
• Need logical sequence
• First check circuit breakers and switches
• Then isolate to dock to power panel
or
• Power panel to outlet or appliance
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AC Troubleshooting
Start
A
Power
to Panel
?
NO
Reset
Service
Breaker
A
Troubleshoot
Dock to Panel
Yes
AC
Main On
?
Yes
Service
Breaker Tripped
Yes
?
NO
NO
Turn AC
Main On
A
Troubleshoot
Panel to
Outlet / Appliance
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Dock to Power Panel
No AC at line side of AC main circuit breaker
• Check/reset dockside circuit breaker
• Check service cord
 Use adapters and AC Outlet Tester
 Power at dockside outlet?
 Power at boat end of cable?
• Check/clean/tighten connectors and wiring
 Disconnect AC power before working on AC
 Use CRC QD Electronic Cleaner on contacts
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Power Panel to Outlet/Appliance
Have AC at load side of branch circuit breaker
•
•
•
•
Reset GFCI outlet
Disconnect AC power before working
Check/clean/tighten wiring at breaker
Check/clean/tighten wiring at
outlet/appliance
• Check wiring with temporary wires from
branch circuit breaker to outlet/appliance
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Summary – Circuit Troubleshooting
DC
•
•
•
•
•
•
Battery tests: Voltage, Load and 3-minute charge
Alternator tests: Drive belt, quick test and wiring
Battery Charger: Quick test, AC power and wiring
Inoperative lights: Bulb, bulb contacts and wiring
DC electronics: Verify DC power & clean contacts
DC wiring: Start at power panel and isolate
AC
• Test outlets yearly
• AC appliances: Verify AC power and check wiring
• AC wiring: Start at power panel and isolate
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Electrical Interference
•
•
•
•
•
Introduction
Sources of Interference
Locating Interference Sources
Interference Suppression
Mitigation Techniques
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Introduction
• Causes and Effects




Caused by rapid on/off current switching
Radiated through air
Conducted though wiring
Degrades high sensitivity electronic equipment
• Noise Layers
 Usually have interference from several sources
 Remove/reduce till acceptable
 Difficult to identify stronger interference
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Sources of Interference
•
•
•
•
•
•
•
•
•
Ignition Systems
Charging Systems
Voltage Regulators
Electric Motors
Gauges and Instruments
Propeller Shaft(s)
Video Displays
Electronic Equipment
Fluorescent Lights
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Identification by Sound
• Ignition
 Popping Sound related to engine speed
• Alternator
 High-pitched musical whine
related to engine speed
• Voltage Regulator
 Intermittent rasping sound
• Electric Motor
 Hissing sound or whine
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Locating Sources
• What is Different?
• What is On?
• How is interference getting into equipment
 Radiated?
 Conductive?
• Pigtail Check (with bypass capacitor)
• Radio Noise “Sniffer”
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Interference Suppression
At source of interference
• Approaches
 Repair or replace faulty equipment
 Shielding to confine interference
 Special-purpose components
to reduce interference
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General Suppression
• Replace/repair faulty equipment
• Correct defective wiring
 Bonding straps still connected?
 Check wiring for loose connections
• Re-run wiring
 Separate power and signal wires/cables
 Dress regulator field wire close to the alternator
• Shielding
 Wires
 Compartments with grounded copper screen
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Ignition System
• Primary
 Shield ignition switch wiring
• Ground shield at engine (only)
 Ground case of ignition coil
 Install 0.1 µf coaxial capacitor
• in positive wire at coil
 Install 0.005 µf disc ceramic capacitor
• at negative terminal of coil
• rated at 1,000 volts
 Replace and adjust breaker points
 Select and replace capacitor
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Ignition System – cont’d
• Secondary
 Install resistor spark plugs
– Install resistor cable (between
distributor and spark plugs)
– Can be used together if needed
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Alternator
• If output less than 50 Amps, add a
0.5 µf coaxial capacitor at output terminal
• If over 50 Amps add a low-pass filter or inline choke at the output terminal
• Never bypass the alternator field
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Charger / Voltage Regulator
Battery charger
• Install near battery and away from electronics
• Suppression built in by manufacturer
• Home-made copper wire shield
Voltage regulator
• May be built in to alternator
• If external
 Mount close to alternator
 Consider shielding field wire (ground both ends)
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Electric Motors
• Well seated brushes
• By-pass with 0.25 to 0.5 µf capacitor
• Ground housing
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Gauges and Instruments
Gauges and instruments
• Bypass with 0.25 to 0.5 µf 200 volt capacitor
• Some may stop working when bypassed
Electric tachometers
• Don’t bypass (it will stop working)
• Shield wire and ground both ends
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Propeller Hash
Shaft Hash
– Indicates stray current or galvanic current problem
• If possible fix problem
– Best to ground the shaft with carbon brushes
– Fixes the symptom, not the problem
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Electronic Equipment
• All electronics and appliances
should be FCC Type Approved
 Part 15 B of the FCC Rules
 Look for decal/label
• Europe has a tougher RFI standard “CE”
 Look for decal/label
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Mitigation Techniques
At equipment being interfered with
• Approaches
 Shielding against radiated interference
 Filtering against conductive interference
• Capacitors (or condensers)
• Chokes (or inductors)
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Shielding and Capacitors
• Shielding for radiative interference
• Capacitor (or condenser)




For conductive interference
Provide low reactance to AC
Placed across (parallel) input power terminals
Bypass undesirable AC noise to ground
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Chokes (Inductors)
• Choke (or inductor)
 For conductive interference
 Provides high reactance to AC
 Placed in series with power wires
• Types of RF chokes
 In-Line
 Snap-On
 Ferrite Data-Line
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Steps
• Ground metal case
• Bypass DC leads
• Bypass and shunt DC leads
• Add choke (in series with DC leads)
• Shield (and ground shield)
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TV Conductive Interference
• Turn AC outlet “Off”
• Install 0.01 µF (micro farad) disc ceramic
capacitor across hot and neutral terminals
 Keep leads as short as possible
• Install snap-on choke in power cord
 5 turns, left to right, on one side or core
 Followed by 5 turns, left to right, on other side
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Summary - Interference
• Locating source




By its sound
What is different?
What is on?
By use of “sniffer”
• Interference suppression (at source of interference)
 Equipment repair
 Specific at equipment
 Shielding of equipment
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Summary – Interference - 2
• New electronics and appliances should
be FCC and/or CE Type Approved
• Mitigation Techniques (at interfered-with equipment)
 Shielding
 Filtering
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