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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 […]
How to Test Electrolytic Capacitors on Circuit Boards Important Note For informational purposes only. If you choose to utilize the concepts in this video, you do so at your own risk. I recommend that any circuit board repairs be supervised by a licensed professional engineer and be done under approved ISO and UL processes. What […]
It Starts with an SCR You can think of an SCR (silicon controlled rectifier) as a diode with a control line. Referring to the image below, the SCR works like a diode in that it will only allow current to flow in one direction – that is to say, current will not flow until the […]
What only Happens in AC Circuits If you look below the surface of a commonly encountered circuit, you might be surprised about what you find. Most of you know that on many Whirlpool refrigerators, a classic Whirlpool icemaker valve solenoid is energized from the icemaker through a 72 ohm heater. So the solenoid and heater […]