MElec-Ch7 - 1

1
Chapter 7

• Basic Troubleshooting
• and
• Repair Procedures

2
Overview

• Tools Needed
• Circuit Troubleshooting
• Electrical Interference

3
Tools Needed

• Multimeters
• Wiring Tools
• Miscellaneous Tools
• Do-It-Yourself Test Tools
• Commercial Testers

4
Multimeter

• Required features in a boats 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

5
Analog Multimeter

• Advantage - Low cost
• Disadvantages
• Difficult to read measurement value
• Have to start at max value and work way down

6
Digital Multimeter

• Advantages
• Easy to read measurement value
• More accurate readout
• Disadvantages
• Have to start at max value and work way down
• Cost

7
Auto-Ranging Multimeter

• Advantage
• Only have to select function (not range)
• DC voltage, DC current, AC voltage or resistance
• Disadvantage - cost

8
Wiring Tools

• Wire Cutter Diagonal Cutter
• 5 or 6 overall
• Plastic cushion grip
• Wire Stripper
• Dont 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

9
Wire Cutters / Wire Strippers
10
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

11
Crimp Tool / Soldering Gun
12
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

13
Pliers / Adjustable Wrench
14
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

15
Screwdrivers
16
Circuit Trouble-Shooting

• Batteries
• Alternators
• Battery Chargers
• Boat Lighting System
• Boat DC Electronic Systems
• Boat AC Circuits

17
Battery Testing

• Hydrometer
• Open-Circuit Voltage
• Load Test
• Three-Minute Charge

18
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
19
Open-Circuit Voltage

• For Maintenance Free, Gel AGM batteries
• When you cant 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
20
Specific Gravity Voltages
Specific Gravity (Flooded Cell _at_ 80 F)
Flooded Cell Voltage
Gelled Cell Voltage
AGM Voltage
Chapter 3 Table 3-5
21
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

22
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

23
Alternator Testing

• Drive Belt
• Quick Test
• Alternator Electrical Connections

24
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

25
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

26
Battery Charger Testing

• Alternator vs Battery Charger
• Quick Test
• Troubleshooting

27
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

28
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

29
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

30
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

31
Lighting Troubleshooting

• Need a logical sequence
• First check circuit breakers and switches
• Then isolate to battery to power panel
• or
• Power panel to light

32
Boat Light Inoperative
Light Working ?
Stop
Yes
NO
Power to Panel ?
Battery Switch On ?
NO
NO
Yes
Troubleshoot Battery to Panel
Yes
DC Main On ?
A
NO
Yes
Troubleshoot Panel to Light
33
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

34
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

35
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

36
Boat AC Circuits

• Testing
• Troubleshooting

37
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

38
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 wont work Defective

39
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

40
AC Troubleshooting
Start
Power to Panel ?
Service Breaker Tripped ?
NO
Yes
NO
Yes
NO
Yes
41
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

42
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

43
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

44
Electrical Interference

• Introduction
• Sources of Interference
• Locating Interference Sources
• Interference Suppression
• Mitigation Techniques

45
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

46
Sources of Interference

• Ignition Systems
• Charging Systems
• Voltage Regulators
• Electric Motors
• Gauges and Instruments
• Propeller Shaft(s)
• Video Displays
• Electronic Equipment
• Fluorescent Lights

47
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

48
Locating Sources

• What is Different?
• What is On?
• How is interference getting into equipment
• Radiated?
• Conductive?
• Pigtail Check (with bypass capacitor)
• Radio Noise Sniffer

49
Interference Suppression

• At source of interference
• Approaches
• Repair or replace faulty equipment
• Shielding to confine interference
• Special-purpose components
  to reduce interference

50
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

51
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

52
Ignition System contd

• Secondary
• Install resistor spark plugs

• Install resistor cable (between distributor and
  spark plugs)

• Can be used together if needed

53
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 in-line
  choke at the output terminal
• Never bypass the alternator field

54
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)

55
Electric Motors

• Well seated brushes
• By-pass with 0.25 to 0.5 µf capacitor
• Ground housing

56
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
• Dont bypass (it will stop working)
• Shield wire and ground both ends

57
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

58
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

59
Mitigation Techniques

• At equipment being interfered with
• Approaches
• Shielding against radiated interference
• Filtering against conductive interference
• Capacitors (or condensers)
• Chokes (or inductors)

60
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

61
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

62
Steps

• Ground metal case

• Bypass DC leads

• Bypass and shunt DC leads

• Add choke (in series with DC leads)

• Shield (and ground shield)

63
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

64
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

65
Summary Interference - 2

• New electronics and appliances should
  be FCC and/or CE Type Approved
• Mitigation Techniques (at interfered-with
  equipment)
• Shielding
• Filtering