BLDC motors aren't new technology in appliances anymore -- in fact, they've become the norm. As such, it's important to be aware of the different configurations you'll see these motors in across appliances. These configurations fall into three categories: 2-wire, 3-wire, and 4-wire.
An important thing to note before we continue: all BLDC motors in appliances are run by inverters. The inverter may be a separate board, like you'll see in washers with BLDC motors, or it may be built into the m
The temperature sensors used in ovens, which are devices called RTDs, don't vary too much between brands and models. There's something of an industry standard for RTD specs that you can generally rely on, even when you aren't given the specs explicitly.
However, Frigidaire has left a booby trap in the form of an RTD with unique specs in some of their ovens. What's more, this difference isn't even properly reflected in some of their tech sheets. They've got incorrect specs!
Want to know
One of the best things we can do to sharpen our skills as techs is to learn from other techs' experiences. There are a number of ways to do that, but the way that's both most convenient and lets you learn from the greatest variety of techs is searching the tech help forums here at Appliantology.
Appliantology has been on the web for 20 years now, and over that time the site has amassed a library of technical knowledge that is unmatched anywhere else. As a member of Appliantology, all of th
At ASTI 2025 in Orlando, FL, I had the honor of teaching a class on reading schematics and troubleshooting using Master Samurai Tech's patented Ten-Step Tango troubleshooting technique. During that class, we did diagnostic workshops on a number of different scenarios, all of which were taken from right here at Appliantology. For those of you who couldn't make it out for the convention, let's run through one of those scenarios here.
We'll be running through the steps of the Tango, but for th
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
Here's your scenario: you're working on a Whirlpool CAM2742TQ2 Washer, and you've determined that the auto temp control (ATC) has failed such that it won't energize the water valves and allow the machine to fill. You intend to replace the ATC, but it's on backorder. Is there any clever trick you can think of that will at least get the customer going temporarily while they wait?
Time to crack out the schematic.
It looks like there's a lot going on here, what with all those alphabe
We’ve all been hearing about R600a refrigerant for years now, and the reality is that it’s no longer an innovation in the area of household refrigeration; it’s the new standard.
With the majority of new refrigerators now being R600a models, repair companies need to be ready to perform sealed system repairs on them. This raises a few questions for these companies: how is R600a different from R134a, and what do I need to service R600a refrigerators?
R600a (let's just call it R600 from he
When you're working on an appliance that's DOA (no lights, no response from the UI), your first troubleshooting priority is to identify where the power supply is missing.
Is it just the UI that's not getting power? Or is the main control board not getting power? Is there even power at the outlet it's plugged into?
These are the questions you need to answer before anything else, and you're going to answer these questions by taking measurements with your meter. However, there are right a
Say you're working on the cooktop of a Frigidaire gas range, and after chasing some wires, you find that this component is in the circuit, right after the power comes in from the outlet:
The label calls it a "signal transformer", but what is the point of this device, exactly? Well, as with most circuit mysteries, the schematic will give us some more insight...
How odd -- a transformer that, seemingly, doesn't do anything. You have 120 VAC going to the primary, and 120 VAC c
Here's a GE microwave schematic. There's a lot of typical microwave stuff going on here, but we're going to focus in on one component today: the monitor switch.
What exactly is this switch's purpose, and how does it affect the circuit?
The purpose of the monitor switch is to act as a safety to prevent the magnetron from being energized while the door is open. The door latch and switches in microwaves are designed so that, if everything is working correctly, the monitor switch sho
The most basic circuit safety device that everyone is familiar with is the circuit breaker. All a breaker has to do is detect if the amperage in its circuit exceeds a certain threshold and open the circuit if it does. Simple and effective, but not every electrical hazard involves excessive current. In fact, having less current than you should can also indicate a serious safety issue. Enter the GFCI and the AFCI.
You might already be familiar with GFCIs (Ground Fault Circuit Interruptors) --
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Many appliance repair techs are intimidated when it comes to troubleshooting control boards. When we talk about "control boards," we're really talking about a single-board computer. After all, we are talking about computers here -- computers that just so happen to run appliances. Samsung is especially famous among techs for being “too electronic” or using too many control boards. Many techs will install a replacement control board from Samsung without running a single test, just to avoid the hea
At one of our recent Live Dojo workshops, a tech shared an interesting problem he had encountered.
He was called out on a GE wall oven where the upper oven lights stayed on all the time, and the door lock wouldn't activate. He investigated further, discovering that when he opened and closed the lower oven door, he heard a relay click as the light turned on and off — but there was no such relay sound for the upper oven.
Presuming this meant a stuck relay on the control board, he went ah
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
Come on a journey with me as we explore just how tangled your circuit analyses can get when you're confronted with conflicting information in a tech sheet.
Here's the Samsung washer schematic we're working with:
Nothing crazy here -- this is pretty standard stuff to see on a Samsung schematic. But when it gets weird is when you try to trace out the power supplies of various loads and board on the schematic with the help of the pinouts elsewhere in the same tech sheet.
Here's
Ever wondered how L1 and L2 in a 240 VAC circuit have a voltage difference of 240 VAC? Or what people mean when they say that L1 and L2 are 180 degrees out of phase? And what exactly do we mean when we say "voltage difference" anyway?
We cover all these topics in this short 6-minute excerpt from one of our many in-depth technical webinar recordings. If you've ever been mystified by the inner workings of standard, split-phase household power, look no further! Give this a watch and be enlight
How does a dryer dry without a vent? Why is there a sealed system in this dryer, just like what you would find in a refrigerator? How well does this model dry clothes compared to a conventional dryer?
All of those are questions we answer as we explore Whirlpool's hybrid heat pump dryer. In this thorough rundown of the machine's key systems and components, we cover topics such as:
The function of the sealed system in this heat pump dryer
How this dryer condenses moisture rathe
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
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
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
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
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
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
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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