Essential Tools for Troubleshooting: Multimeters, Wiring, and More

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 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. 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 • 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. 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

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

20. Specific Gravity & Voltages Specific Gravity (Flooded Cell @ 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 Replace / Check Bulb A A Turn Battery Switch On Turn DC Main On 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 Cleaneror 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 won’t 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. A A A Reset Service Breaker AC Main On ? Turn AC Main On Troubleshoot Dock to Panel Troubleshoot Panel to Outlet / Appliance 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