Should you Reference Neutral when Testing 240v Circuits? How many times have you heard a technician state “I’m getting 120v on both sides of the element and it still doesn’t get hot”? Technicians can get confused when working on an appliance that has lost L2, for example. If L1 feeds through a dryer element and […]
Appliance and HVAC Technician Electrical References Below are links to all Appliance Technician Quick-References to date. Feel free to bookmark/share this page or the individual pages below. These are updated as often as needed: 120v Point-to-Point Troubleshooting Cheat Sheet – CLICK HERE 120V Point-to-Point Voltage Pen Diagnostics Cheat Sheet – CLICK HERE 240v Point-to-Point Troubleshooting […]
Intro to the Relay Testing Cheat Sheet This blog shows a diode trick and checklist for fast testing of relays, as well as determining the relay coil voltage. The checklist is further down in this blog. Important Note Never attempt to repair circuit boards in appliances or HVAC systems unless you are directly supervised by […]
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The Tech Circuit’s mission is to better educate Appliance and HVAC Technicians in the area of electrical and electronics diagnostics and repair. There is clearly a need for increased education in this area – and the effort is endless. Although I thoroughly enjoy this mission, it does take time to maintain TechCircuit.org and the Tech […]
Correct and Incorrect Terminal Block Connections For many 240v appliances that plug into a receptacle, there are two common types of power cords. One is old-style 3-wire cord and the other is a relatively new 4-wire cord. Disclaimer: THIS BLOG IS INTENDED FOR APPLIANCE TECHNICIANS ONLY. ALWAYS USE APPROPRIATE SAFETY PRECAUTIONS WHEN WORKING WITH ELECTRICITY. […]
Intro This article, for beginning to experienced appliance technicians, explains some of the more commonly found 120v and 240v Appliance circuit topologies and describes how to perform their respective point to point voltage check diagnostics for brute-force isolating of failed components. Please note that this article is not or DIY (do it yourselfers), as it […]
Intro – Series Circuit Rules When troubleshooting series circuits, you can rely on certain rules based on Ohm’s law. Rule #4 is most important when troubleshooting series circuits with only one load. This is because a break in the circuit represents “infinite” resistance. That break will thus have the full supply voltage across it. Illustration […]
Brute Force Electrical Diagnostics A systematic approach to finding failed components is a more definitive way to troubleshoot electrical problems with appliances. I recommend using the LoZ function of your multimeter if you have it. Below are point-to-point voltage drop testing methodologies for both 240v and 120v appliances. 240v Point-to-Point™ Voltage Testing 120v Point-2-Point™ Voltage […]
Electricity Course and Quiz for Appliance Technicians It is important to understand electricity basics when servicing appliances. After all, you will need to electrically troubleshoot them sooner than later. You don’t want to be the Technician that encounters a simple electrical problem, and be unable to complete your diagnosis. If you have even a basic […]