1. MElec-Ch7 - 1 Chapter 7 Basic Troubleshooting and Repair Procedures Basic Troubleshooting and Repair Procedures

2. MElec-Ch7 - 2 Overview Tools Needed Circuit Troubleshooting Electrical Interference Tools Needed Circuit Troubleshooting Electrical Interference

3. MElec-Ch7 - 3 Tools Needed Multimeters Wiring Tools Miscellaneous Tools Do-It-Yourself Test Tools Commercial Testers Multimeters Wiring Tools Miscellaneous Tools Do-It-Yourself Test Tools Commercial Testers

4. MElec-Ch7 - 4 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 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

5. MElec-Ch7 - 5 Analog Multimeter Advantage - Low cost Disadvantages  Difficult to read measurement value  Have to start at max value and work way down Advantage - Low cost Disadvantages  Difficult to read measurement value  Have to start at max value and work way down

6. MElec-Ch7 - 6 Digital Multimeter Advantages  Easy to read measurement value  More accurate readout Disadvantages  Have to start at max value and work way down  Cost Advantages  Easy to read measurement value  More accurate readout Disadvantages  Have to start at max value and work way down  Cost

7. MElec-Ch7 - 7 Auto-Ranging Multimeter Advantage  Only have to select function (not range) DC voltage, DC current, AC voltage or resistance Disadvantage - cost Advantage  Only have to select function (not range) DC voltage, DC current, AC voltage or resistance Disadvantage - cost

8. MElec-Ch7 - 8 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 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

9. MElec-Ch7 - 9 Wire Cutters / Wire Strippers

10. MElec-Ch7 - 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 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. MElec-Ch7 - 11 Crimp Tool / Soldering Gun

12. MElec-Ch7 - 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” 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. MElec-Ch7 - 13 Pliers / Adjustable Wrench

14. MElec-Ch7 - 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 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. MElec-Ch7 - 15 Screwdrivers

16. MElec-Ch7 - 16 Circuit Trouble-Shooting Batteries Alternators Battery Chargers Boat Lighting System Boat DC Electronic Systems Boat AC Circuits Batteries Alternators Battery Chargers Boat Lighting System Boat DC Electronic Systems Boat AC Circuits

17. MElec-Ch7 - 17 Battery Testing Hydrometer Open-Circuit Voltage Load Test Three-Minute Charge Hydrometer Open-Circuit Voltage Load Test Three-Minute Charge

18. MElec-Ch7 - 18 Hydrometer Hydrometer – best tester of flooded-cell  Measures Specific Gravity  Chapter 3, Table 5 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 Discharged1.120

19. MElec-Ch7 - 19 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 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 VoltageFloodedGelAGM 100 % charge 12.6512.9012.85 75 % charge 12.412.6512.6 50 % charge 12.212.3512.3 25 % charge 12.0 Discharged11.8

20. MElec-Ch7 - 20 Specific Gravity & Voltages Chapter 3 Table 3-5 Specific Gravity (Flooded Cell @ 80 F) Flooded Cell Voltage Gelled Cell Voltage AGM Voltage

21. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 23 Alternator Testing Drive Belt Quick Test Alternator Electrical Connections Drive Belt Quick Test Alternator Electrical Connections

24. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 26 Battery Charger Testing Alternator vs Battery Charger Quick Test Troubleshooting Alternator vs Battery Charger Quick Test Troubleshooting

27. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 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 Need a logical sequence First check circuit breakers and switches Then isolate to battery to power panel or Power panel to light

32. MElec-Ch7 - 32 Replace / Check Bulb Boat Light Inoperative Light Working ? Stop Yes NO Power to Panel ? NO Yes Battery Switch On ? A Turn Battery Switch On NO A DC Main On ? Turn DC Main On NO A Yes Troubleshoot Battery to Panel Troubleshoot Panel to Light

33. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 36 Boat AC Circuits Testing Troubleshooting Testing Troubleshooting

37. MElec-Ch7 - 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” 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. MElec-Ch7 - 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 won’t work = Defective 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

39. MElec-Ch7 - 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 Need logical sequence First check circuit breakers and switches Then isolate to dock to power panel or Power panel to outlet or appliance

40. MElec-Ch7 - 40 AC Troubleshooting NO Power to Panel ? Yes Service Breaker Tripped ? Reset Service Breaker NO A AC Main On ? Turn AC Main On NO A Yes Troubleshoot Dock to Panel Troubleshoot Panel to Outlet / Appliance A Start

41. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 44 Electrical Interference Introduction Sources of Interference Locating Interference Sources Interference Suppression Mitigation Techniques Introduction Sources of Interference Locating Interference Sources Interference Suppression Mitigation Techniques

45. MElec-Ch7 - 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 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. MElec-Ch7 - 46 Sources of Interference Ignition Systems Charging Systems Voltage Regulators Electric Motors Gauges and Instruments Propeller Shaft(s) Video Displays Electronic Equipment Fluorescent Lights Ignition Systems Charging Systems Voltage Regulators Electric Motors Gauges and Instruments Propeller Shaft(s) Video Displays Electronic Equipment Fluorescent Lights

47. MElec-Ch7 - 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 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. MElec-Ch7 - 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” What is Different? What is On? How is interference getting into equipment  Radiated?  Conductive? Pigtail Check (with bypass capacitor) Radio Noise “Sniffer”

49. MElec-Ch7 - 49 Interference Suppression At source of interference Approaches  Repair or replace faulty equipment  Shielding to confine interference  Special-purpose components to reduce interference At source of interference Approaches  Repair or replace faulty equipment  Shielding to confine interference  Special-purpose components to reduce interference

50. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 52 Ignition System – cont’d Secondary  Install resistor spark plugs Secondary  Install resistor spark plugs –Install resistor cable (between distributor and spark plugs) –Can be used together if needed

53. MElec-Ch7 - 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 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. MElec-Ch7 - 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) 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. MElec-Ch7 - 55 Electric Motors Well seated brushes By-pass with 0.25 to 0.5 µf capacitor Ground housing Well seated brushes By-pass with 0.25 to 0.5 µf capacitor Ground housing

56. MElec-Ch7 - 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 Don’t bypass (it will stop working) Shield wire and ground both ends 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

57. MElec-Ch7 - 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. MElec-Ch7 - 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 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. MElec-Ch7 - 59 Mitigation Techniques At equipment being interfered with Approaches  Shielding against radiated interference  Filtering against conductive interference Capacitors (or condensers) Chokes (or inductors) At equipment being interfered with Approaches  Shielding against radiated interference  Filtering against conductive interference Capacitors (or condensers) Chokes (or inductors)

60. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 62 Steps Ground metal case Shield (and ground shield) Bypass DC leads Bypass and shunt DC leads Add choke (in series with DC leads)

63. MElec-Ch7 - 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 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. MElec-Ch7 - 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 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. MElec-Ch7 - 65 New electronics and appliances should be FCC and/or CE Type Approved Mitigation Techniques (at interfered-with equipment)  Shielding  Filtering New electronics and appliances should be FCC and/or CE Type Approved Mitigation Techniques (at interfered-with equipment)  Shielding  Filtering Summary – Interference - 2