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Appliance Repair Tech Tips

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How Does the Lid Lock Circuit Work in a Top-Load Washer?

Let's crack out our schematic-reading skills and take a look at a seemingly straightforward washer lid lock circuit. Notice that, while they give us labels for the pins, that's basically all we've got as far as specs or info about the control board's algorithm. So if we want to figure out how this circuit works during operation, we'll have to crack out some Circuit Fu™. That means using both our understanding of electricity and our understanding of the intended function of a lid lock

Son of Samurai

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How to Correctly Measure Dryer Vent Airflow

The general rule for dryer vent airflow is that, if the airflow feels like a breath (even a strong one), then you have a problem. This rule of thumb will serve you well a lot of the time, but sometimes a "calibrated palm" just isn't enough. Sometimes, you need to get an actual measurement of the airflow so that you can compare it to the specifications. What you really want to know is the volumetric flow rate of the dryer exhaust. That is, how much air it's pushing out over a particular peri

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How does this Dishwasher Motor with Triacs and Three Windings Work?

Take a look at this motor circuit: Three different windings? Triacs in the circuit? A "sense resistor"? What's going on here? As it turns out, there's nothing really new or different happening here. In fact, all we're looking at is a standard split-phase motor with two different start windings. One is the start winding when the motor functions as a drain pump, and the other is for when the motor functions as a wash pump. Here's what the circuit looks like when the drain wind

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How to Identify DC Power Supplies in Appliance Schematics

While all appliances use the same fundamental technology, their manufacturers often talk about them using different terms. Let's talk about DC power supplies and how not to get tripped up by the different terminology used there. First off, the very basics. Just like in AC, any DC circuit needs two legs: the voltage supply, and the return. The return is called Ground in DC. Don't let that confuse you -- DC ground is NOT AC ground-- they are electrically distinct and separate. Ground is to DC

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Can You Find the Cause of These Four Inop Loads in a Thermador Refrigerator?

Got a fun one for you today, pulled right from the annals of Appliantology. That's right -- a tech just like you encountered this whacky problem and figured it out. Here's the weird scenario: several different loads aren't working on this Whirlpool-built Thermador refrigerator. The water and ice dispensers, the dispenser light, and the freezer light are all inop. Wow, four different loads all happened to fail at the same time! Crazy, right? A lesser tech might have gone full PCM and st

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Detailed Washer Timer Chart Breakdown and Cooktop Light Weirdness

Reading timer charts may just seem like an old-skool skill for a bygone era of appliances, but there are still plenty of these old workhorses around that need troubleshooting. Plus, analyzing these circuits teaches you a lot of schematic mojo that is useful in all areas of appliance repair. In our latest Live Dojo workshop, we worked through how to read this timer chart and schematic in harmony with each other. You can't understand the schematic without the timer chart, and vice versa. Topi

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Functional Understanding of Circuits: the Key to Reading Unclear Schematics

Got a fun exercise for you today: let's use our electrical and schematic know-how to figure out how a circuit works in a schematic that leaves out a lot of useful labelling. The circuit we're interested in is the one labelled Door safety interlock. Based on its name and its context within the schematic -- it gates Line to a number of loads elsewhere in the appliance -- this circuit contains the door switch and the door lock. But how exactly does it work? We can assume that the sw

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Microwave Madness and Meter Category Demystification Double Feature

This microwave will run with the door open -- lucky for the customer, it also doesn't heat. But why is the turntable able to run with the door open? What do you do when a circuit doesn't work at all the way it's supposed to? That's exactly what we discussed in our latest Live Dojo workshop.  Topics covered include: Microwave door interlock switches Turntable motor circuit analysis Control board algorithms and relays Theorizing a reasonable failure scenario

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Read Timer Charts with Certainty Using the Timer Chart Cha-Cha

Timer charts may be for old-skool appliances with mechanical timers, but there are still plenty of old-skool appliances knocking around, so reading timer charts remains a vital troubleshooting skill. That's exactly what we cover in this workshop: how to cohere the timer chart and the schematic, reading them in tandem. Kind of like they're dance partners in the Timer Chart Cha-Cha! Topics covered in this workshop include: How to decipher the rows and columns on a timer chart

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How to Troubleshoot Control Boards with Confidence

When a control board doesn't seem to behave the way it's supposed to, does that mean it's always time to replace the board? How do you avoid the dreaded callbacks on service calls where you replaced the board because you had no idea what else to replace? Is there a way to reliably troubleshoot computer-controlled appliances and avoid guesswork when it comes to the control board? Of course there is, and Team Samurai is going to show you how! It all boils down to understanding how these

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Schematic Basics: LG Wall Oven No Heat

Got a short and sweet one for you today. Here's the scenario: You're troubleshooting an LG wall oven that doesn't heat. You've gone ahead and torn it down as much as you could to do an ohms measurement on the broil element (in spec) and the temperature sensor (also in spec). You confirmed that the unit was getting a good 240 VAC power supply. You wanted to test the bake element too, but you didn't have a second man with you, so you gave up on that idea. Instead, you just replaced the main c

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Quick Tips on How to Troubleshoot Relays, Triacs, and Diodes

When it comes to switches in appliances, it's hard to think of one more ubiquitous than the relay. It can be used with and without a control board, and it allows a small voltage to control a much larger voltage. But what exactly does that mean, and how do they do that? And what about triacs, the relay's solid-state cousin? We cover both of these devices, including how they work and how to troubleshoot them, in detail in this excerpt from one of our recent Live Dojo workshops. Give it a watc

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[Video] How to Use a Loading Meter to Identify Ghost Voltage AND Watch the Samurai Electrocute Himself!

Ghost voltage has misled many a green tech during his troubleshooting. How are you supposed to interpret it when the VAC function of your meter tells you that you have 108 volts going to a load? Is your voltage supply bad? Or are you perhaps simply missing your Neutral? That's where a loading meter comes to the rescue. By actually putting a load on a circuit, the loading meter shows if there really is the difference in voltage between those two points required for current to flow. No N

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Schematics vs. Wiring Diagrams -- Do You Know the Difference?

Schematics and wiring diagrams -- two different kinds of service documents that seem similar, but actually serve completely different purposes. One of them is essential to any electrical troubleshooting and should be consulted on every service call, while the other has much more niche applications. But which is which, and how do you tell them apart? That's what we explore in this workshop, which is an excerpt of the discussion from one of our latest Live Dojo workshops. In it, we go through

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Son of Samurai in Tech Talk

[Video] Demystifying Strip Circuits and Confusing DC Terminology

What are strip circuits and how do you read them? What purpose do they serve in troubleshooting? Are they better than normal schematics, worse, or just different? That's what we explore in this workshop, which is an excerpt of the discussion from one of our latest Live Dojo workshops. Parallel to that, it also acts as something of a part 2 to our previous workshop on DC terminology. These schematics that we show have a number of esoteric and straight up confusing DC terminology, but don't w

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A 2-Step Training Plan to Achieve Total Refrigerator Repair Mastery

Refrigeration is its own little world within appliance repair. The presence of a sealed system introduces all kinds of specific knowledge and skills you need to have to properly troubleshoot these machines, from thermodynamics to compressor technology to brazing. And that's not even mentioning the other systems, like airflow and control. So how do you learn all this stuff? Well, if you want to troubleshoot refrigerators like a real tech, you'll need both brains-on and hands-on trainin

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[Video] How to Never Get Tripped Up By DC Terminology in Schematics Again

DC power in appliances works the same way no matter the manufacturer, but everyone has their own way they like to talk about it. And if you're not up on the lingo, you'll be left mystified by DC circuits in schematics. You don't have to worry, though, because we explain all kinds of DC terminology in this latest workshop. From VDC to VCC, we cover everything you're likely to encounter in your troubleshooting travels through DC power, including: Terms for DC voltage supplies T

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A Hands-On Demonstration of PWM and RPM Signals in BLDC Motors

We had some fun in this Live Dojo Workshop! We went beyond the screen into the big, scary Real World and showed off live a few things about BLDC fan motors, including: BLDC fan motor wire color conventions Expected readings on PWM and RPM feedback lines Simulating a PWM signal Identifying failed speed sensor ...and more! Click below to watch the workshop recording -- viewable only by premium tech members. If you're an Appliantology tech member and y

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Take a Peek at the Guts of a Linear Compressor...

Linear motors -- primarily in the form of linear compressors -- aren't new technology, but they've only been migrating into the appliance world over the past few years. These "new" compressors have their own unique failure modes and troubleshooting dos and don'ts. To really have a good idea of how to diagnose them, you need to understand how they work. That's exactly what we show in this short excerpt from one of our longer technical training webinars. Give it a watch and learn something!

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Son of Samurai in Tech Talk

How to Catch Loading Down in DC Power Supplies Before It Catches You

Loading down is a failure scenario unique to DC power supplies, and if you don't know what to look for, it can leave you scratching your head and eating some expensive parts. How do you identify that you have a potential loading down scenario, and what steps can you take to verify that? That's exactly what we cover in this Master Samurai Tech Workshop. Topics covered include: How DC power supplies work How they affect the board's operation What loading down is and how

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Maytag Dryer with a Missing Neutral: Will It Still Run?

It's always the old-skool style circuits that have the most interesting electrical issues, isn't it? In this workshop, we took a look at just one such machine. A missing neutral in the power supply doesn't have the effect that you would necessarily expect. For example, in this dryer, the timer motor runs on 240 VAC, but the drive motor runs on 120 VAC power. With a missing Neutral, the drive motor won't run, but the timer motor will. We go all into that, as well as the kind of troubleshooti

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Motor Specs Demystified -- and More Sizzling Live Dojo Workshop Discussions!

How are we as techs supposed to understand the specifications we see on a split-phase motor's label? What's the difference between a motor's output power and its input power, and which of those specs is given on the label? What do acronyms like FLA and LRA mean? All that and more covered in this short video on motor specifications. This is just a short excerpt from the great technical discussions we have every other Saturday during our Live Dojo Workshops. If you're not joining us for these

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How Do the High-Voltage Circuit and Magnetron in a Microwave Work?

We're going to take a dive into what exactly is going on electrically with the high-voltage circuit in a microwave. We'll use this specific schematic as an example, but these principles apply generally. Don't worry about most of the schematic. All that matters to us right now is the high-voltage section -- the transformer on the right side of the schematic and everything to its right. If you're not familiar with how magnetrons work (or even what they are), then this circuit

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Diagnostic Modes: What They Can Do and How to Use Them

Some techs long for the "good old days" of mechanical controls, when troubleshooting appliances was supposedly simpler. But the universal use of electronic controls nowadays actually provides many troubleshooting benefits -- in particular in the form of error codes and diagnostic modes. The purpose of error codes is for the control to tell you its best guess of what's wrong, based on the algorithms programmed into it by the engineers. Note that the engineers' best guess is sometimes a very

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[Video] How Do Microwave Interlock Switches Work?

Why are microwaves so picky about the way they do their door switches? Are two different interlock switches really necessary? And what does the monitor switch even do, anyway? All these questions and more answered in this short instructional presentation. Big props to Brother @Vance R for his explanation of these switches in this topic, which inspired us to make this video. Topics covered include: Schematic analysis of interlock switch circuits Identifying if the schemat

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Son of Samurai in Tech Talk

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