Click here to check out our structured, online appliance repair training courses for rookies and experienced techs.

FAQs | Repair Videos | Academy | Newsletter | Podcast | Contact

Stay connected with us...

Subscribe to our YouTube channel for lots of appliance repair tips and help! Subscribe to our MST Radio podcast to learn secrets of the trade. Sign up for our free newsletter and keep up with all things Appliantology.
  • Announcements

    • Samurai Appliance Repair Man

      Webinar Recordings Index Page   03/02/2018

      On-demand appliance repair training videos for Professional Appliantologist members Over 30 hours (and growing!) of original, high quality appliance training webinars developed and given by yours truly are at your fingertips, on topics you won't find anywhere else. Fill in those knowledge gaps, strengthen those areas of uncertainty, and boost your skills. Watch on mobile or desktop at your convenience whenever, wherever.  Ultra Short Primer on Basic Electricity, Circuits, Ohm's Law, and Schematic Reading (Length: 1:04:48) Basic Refrigerator Troubleshooting (Length: 1:10:45) Schematic Reading Workshop, 10/2015 (Length 1:19:08) Troubleshooting Strategies for Computer-Controlled Appliances (Length: 48:34) Semiconductors and PN Junctions (Length: 1:04:37) Appliance Temperature Sensing Devices & Technology (Length: 1:27:33) Voltage Measurements, Meters, Ghost Voltages, and Triac-controlled Neutrals (Length: 1:29:32) Troubleshooting with Tech Sheets, Part 1, 4/2016 (Length: 1:09:26) Troubleshooting with Tech Sheets, Part 2, 4/2016 (Length: 1:21:11) Tech Sheet Review, 4/9/2016: Bosch Speed Cooker, Amana Refrigerator, GE Glass Cooktop Range (Length: 1:22:58) Pulse Width Modulated (PWM) Switches used in Samsung Switched Mode Power Supplies (SMPS) (Length: 27:07) PWM Computer Cooling Fan in a Whirlpool Refrigerator (Length: 14:53) Understanding AC Split-phase Household Power Supplies (Length: 52:41) Troubleshooting a Samsung Electric Dryer without Disassembly using Live Tests and the Schematic (Length: 22:47) Troubleshooting a Bosch Dishwasher No-Heat Problem using the Schematic and Live Tests (Length: 15:38) Linear Motors and Linear Compressors (Length: 55:54) Bi-directional PSC Drive Motor Systems in Whirlpool VM Washers (Length: 56:52) Appliance Service Call Structure and Troubleshooting Strategies (Length: 1:00:16) The Ten Step Troubleshooting Tango and Workshop Exercises (Length: 1:35:39) Troubleshooting Ten-Step Tango Advanced Workshop (Length: 1:32:06) Ten-Step Tango Troubleshooting Workshop: Refrigerators (Length: 1:35:57) Whirlpool Duet Washer Schematic Analysis & Whirlpool Dryer Moisture Sensor System (Length: 1:03:04) Neutral Vs. Ground, Inverter Microwave, Digital Communications, Loading Down in DC loads, and more! (Length: 1:14:45) Gas Oven Service Call After a Parts Changing Monkey (Length: 36:04) AFCI and GFCI Circuit Protection Technology (Length: 41:26) Troubleshooting Samsung Refrigerators and more (Length: 1:29:58) 3-way Valves and Dual Evaporator Refrigerators (Length: 1:15:45) Split-Phase Compressors and PTC Start Devices (Length: 1:11:57) Gas Dryer Ignition Systems (Length: 53:50) Refrigerator Sealed System Thermodynamics, Part 1 (Length: 43:07) Refrigerator Sealed System Thermodynamics, Part 2 (Length: 1:09:09) Refrigerator Sealed System Thermodynamics, Part 3 (Length: 1:11:56) Refrigerator Sealed System Thermodynamics, Part 4 (Length: 37:45) Refrigerator Sealed System Thermodynamics, Part 5 (Length: 16:35) Appliantology Peer Group web meeting, Feb 25, 2018 (Length: 1:47:30) Appliantology March 2018 Peer Group Meeting (Length: 1:59:58) To access these webinars and all the other info-goodies here at Appliantology, become a Professional Appliantologist today. If you need cost-effective, time-flexible, state-of-the-art appliance technical training, check out the Master Samurai Tech Academy.
Samurai Appliance Repair Man

Making Basic Electrical Measurements

Recommended Posts

Samurai Appliance Repair Man

[align=left]Appliances are electro-mechanical devices-- that's a fancy word that means they have electrical and mechanical parts. This also means that appliances can have either electrical or mechanical failures. Most people with one eye and half a brain in their skull can figure out the mechanical part. But very few do-it-yourselfers have even the basic skills needed to troubleshoot an electrical problem in an appliance such as reading a schematic and wiring diagram and using an inexpensive multimeter, like the one shown below ($15), to make electrical measurements.



Reading wiring diagrams and schematics is something I do all the time on the job. But if you don't know how to use a basic multimeter to make two simple electrical measurements, then you don't have a prayer of troubleshooting even the most minor electrical problem--all you'll be able to do is guess about which part might be bad. That's what we call the Shotgun Parts Changing School of Appliance Repair.

Ok, grab 'hold of those two large lumps at the base of your spine and let's light this candle.

Resistance and Continuity Measurements


Using a Multimeter to Measure Continuity or Resistance[/align]

The picture above shows how to measure resistance (click it for a larger view). Resistance is measured in units called "ohms." You'll commonly want to know the resistance of things like bake elements and solenoid coils. For example, a good bake element typically has a resistance of about 30 ohms. If your oven's not baking and you measure the resistance of the bake element and the meter doesn't move, then you know you'got a bad element.

A special type of resistance measurement that we commonly make in the field is a continuity measurement. When we're testing continuity, we don't care what the actual resistance is, we just want to know if the thing being tested (switch, wire, fuse, etc.) will allow electricity to flow through it. Continuity is a "yay" or "nay" measurement, a component either has continuity or it doesn't--it's kinda like pregnancy in that sense.

Two things to remember when making resistance measurements: 1) the circuit should be de-energized (for those of you in Palm Beach, this means to unplug the appliance first!) and 2) remove at least one wire attached to the component you're testing to disconnect it from the rest of the circuit so you're not getting a false reading by measuring through the rest of the circuit.

You wouldn't believe the number of grasshoppers I talk to who just off and changed the bake element when the oven didn't work only to find that that wasn't the problem! A simple ohm measurement would've saved them a lot of money and headache. But, some people can't be bothered with a bunch of "useless theory."

Voltage Measurements


Using a Multimeter to Measure Voltage[/align]

The picture above shows how to measure voltage. A voltage measurement at the outlet should be the first thing you do whenever you have an appliance that is completely inoperative, or if you have an electric dryer that's not heating, or an electric range that doesn't get hot enough. You'll need to know the basic anatomy of these various electrical outlets to know what to measure for. Check out the links below for illuminating illustrations of these outlets:

Obviously, to measure voltage, there must be power present. This means you can have a hair-raising experience if you touch the wrong thing with your bare hands. As long as you're holding the probes by the insulated handles and are careful about where you place the metal points of the probes, you'll be fine. I've been working with electricity for over 30 years and I still get shocked every now and then. It only hurts a little, kinda like a snake bite, and it fades quickly. So don't freak out.

Besides the outlets, you'll frequently need to measure voltage at various points inside the appliance. Usually, you're measuring this voltage with respect to ground. That just means that you can clamp one probe to an unpainted metal place on the appliance chassis and then touch the other probe to the points of interest. Your other hand should either be tucked in your pocket or behind your back. This way, you won't get shocked because you won't be giving the current a path to flow through your body. Easy, da?

Current Measurements


Using a Clamp-on Amp Meter to Measure Current[/align]

Here's a clamp-on ampmeter (or amp meter) being used to measure current flow through a wire. This is a common test for determining whether or not a gas oven ignitor is good or bad--the only way to really know is by measuring its current draw and comparing to rated draw. And, yes, Homer, the ignitor can glow orange and still be bad.

You'll also want to measure current draw in cases where you have an electric motor that runs a few minutes then shuts off to see if the problem is with the motor drawing excessive current.

Recommended reading:


[align=center]Buy Appliance Parts Here[/align]


Share this post

Link to post
Share on other sites

Need appliance parts? Call 877-803-7957 now!

Samurai Appliance Repair Man

Ready for the next step?  Here's a more comprehensive guide on using test equipment.  From Whirlpool Corporation:

(22mb, pdf file)

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now