We're all familiar with how thermistors work: their resistance varies with temperature, which in turn varies the voltage drop across them. The control board then reads that voltage drop and determines the sensed temperature based on that.
But those with a bit of basic electricity knowledge might scratch their heads a bit if they think about this. Thermistors are almost always drawn on schematics such that they aren't in series with anything else -- it gets its 5 VDC supply and DC ground dir
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
Here's our scenario: you're working on a Samsung WA50K8600AW washer that won't advance in the cycle. Error codes and test modes aren't telling you anything useful, and the control doesn't even seem to be trying to advance the cycle. You've checked the air tube connected to the pressure sensor, too, and everything is clear there.
What can you do here? Do you just call it a bad board and move on?
Let's see if there's a smarter test we can do on this one. What if we could test the signal
Greetings, my brethren in the craft!
I wanted to give you all a heads up about the server migration that's currently in progress here at Appliantology. You shouldn't notice too much amiss while this is going on (besides some downtime early Saturday morning when the actual transfer takes place), but there may still be some weirdness. For example, we just noticed that some PA membership renewal notices just got sent out to a few of our users that had already renewed within the past few weeks.
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
Take a look at the circuit for this electric cooktop element. Notice anything odd about it?
Looks pretty straightforward, right? Well, it certainly is straightforward when the simmer switch isn't closed. Here's what the circuit looks like when it's not running on simmer.
L1 goes through the simmer select board and a temperature-controlled switch, and L2 goes through the relay board and a couple other switches. Standard stuff for one of these elements.
But what's going
If you read my previous post about sealed system basics, you know that understanding the thermodynamic states of refrigerants (saturated, subcooled, and superheated) is essential to sealed system troubleshooting. In that post, I explained these states in terms of a simple pressure-temperature table. While that keeps things simple, it doesn't really give you a strong visual and mental model for how the refrigeration cycle works thermodynamically.
That's why we're going to spend this whole po
When you want to measure the voltage across a component, where do you go to do that? Do you just resign yourself to disassembling the machine until you have access to that component?
If you want to troubleshoot like a real tech, you use EEPs -- that's Electrically Equivalent Points. Identifying EEPs requires both being able to skillfully read a schematic and having a solid understanding of how electricity works. By doing this, you eliminate all unnecessary disassembly, increasing the profit
Gas burners are a whole little microcosm within appliances with some interesting technology that we don't see much elsewhere. In this webinar recording, we cover how to troubleshoot various cooktop ignition systems, covering topics such as:
DSI systems
Single-point ignition
Reignition systems
Continual sparking after a flame is established
Applying the Ten-Step Tango to real-world problems
...and more!
Click below to check out this webinar record
What do you do when a seemingly simple problem stumps you? Well, it's times like that when it's essential to have a structured troubleshooting strategy like the Samurai's Ten-Step Tango.
What is the Ten-Step Tango and how do you use it? That's exactly what we're going to teach you all about in this webinar recording, using a real-life example from here at Appliantology: an LG electric wall oven that won't heat. Strange as it may seem for such a simple problem, most techs would troubleshoot
Here's a scenario taken right from the trials and tribulations of an Appliantology tech: you're troubleshooting a no heat complaint on a GE electric dryer. You start your troubleshooting with the heating circuit, and your findings are puzzling: there are 120 volts on either side of the heater with respect to neutral, but when you do a voltage reading across the heater, you get some weird amount like 80 volts. What gives?
There are a couple of things going on here, and one is easily remedied
Here's the situation: our tech has a Whirlpool dishwasher that does everything normally, except the wash motor simply won't run.
He's done his due diligence and checked for voltage to the motor -- with a LoZ meter, even! -- and what he's finding is puzzling. It looks like the voltage is jumping around from 0 to 120 VAC erratically. What does this mean? Could it be a bad board?
As with all good troubleshoots, let's start with the schematic. Here's just the motor circuit:
Now,
I've got another scenario for you, taken right from the trials and tribulations of an Appliantology tech. Here's the situation: you're working on a top-load washer, and whenever you try to run a cycle, the tub doesn't move and the motor just hums.
Right away, we have a decision to make: do we go ahead and tear apart the machine to take a look at the wash motor? After all, there are a number of mechanical failures that could cause these symptoms. Maybe we should just go ahead and get our han
It should always be our goal to get our diagnosis with as little disassembly as possible using our schematic-reading know-how, but did you know that you can sometimes track down the problem without any disassembly at all?
That's just what the Samurai did for this Thermador gas range. Want to learn how he pulled off this magic trick? Watch the video below.
Want to watch the full recording? Click below -- viewable only by premium members.
Join me on another short troubleshooting journey -- this one taken from a real tech's experience that he posted on Appliantology.
You're troubleshooting a Samsung dryer that won't start-- the control panel will let you select a cycle, but it won't actually run if you press the start button. But the real head-scratcher is that, despite not being able to start a cycle, the machine always runs when the door is closed.
Sounds tricky, but as you'll see, the troubleshoot is pretty simple if
We techs should always be looking to sharpen our repair skills, and one of the best ways to do that is to learn from each other's experiences.
In this excerpt from a longer webinar, the Samurai walks through a Bosch dishwasher no heat problem that he encountered, working through his thought process and schematic analysis step by step. Watch it and learn a thing or two!
Want to watch the full webinar recording? Click below -- viewable only by premium members.
We're so used to our fancy control boards and computer-controlled appliances that we sometimes forget how to troubleshoot old-skool circuits. While these circuits are generally pretty straightforward, the manufacturers employed some clever tricks that can mess with your head if you don't have a firm grasp of simple AC circuits.
Take the buzzer in this dryer as an example:
The Tan or Black side of the buzzer goes straight to neutral through that unlabeled switch beneath the temper
We're taking a step back from our fancy electronics to the good ol' days of simple AC circuits. Well, I say "simple", and that is true -- but engineers back then had to pull out all the stops and do some pretty cool tricks to get the functionality they wanted. This means that, to really understand what's going on in these older circuits, you need to have a firm grasp of both AC circuits and the technology used.
In this webinar, we:
Work through 4 real-world dryer case studies that h
No matter what refrigerator problem you're called out for, no matter if it's for a warm freezer or a noisy fan or a leaking dispenser, there's one simple step that should you should always do before anything else -- before you or the customer even opens the doors of the machine:
Measure the compartment temperatures.
Simple, right? So why am I writing a blog post about it? Well, a lot of techs don't see why this is a step that you must always take when troubleshooting a refrigerator. Do
We've got a toughie for you to figure out today. The tech in this scenario has been out on this dryer multiple times now, and the problem just won't go away. The heating element keeps going open, and the timer motor keeps stalling and not completing cycles. He's verified a good 240 VAC power supply to the timer and replaced both parts multiple times, but the problem keeps recurring every few months. What gives?
Let's board the train away from PCM-Land and use one of our foundational trouble
We techs rely on accurate technical documentation to do our jobs. You can't make a troubleshooting plan or make meaningful electrical measurements without a good schematic. But what do you do when your technical info contradicts itself?
Let's take a look at this Whirlpool refrigerator, specifically focusing on the evaporator fan. Here it is on the schematic, marked up for your viewing pleasure:
Looks like a standard 120 VAC fan motor. But now, let's take a look at some of the wri
The very first step in troubleshooting a broken appliance happens long before the tech sets foot in the customer's home. In fact, it can happen even before the tech knows about the service call. We're talking about formulating a problem statement.
What I mean by a problem statement is very specific. A valid problem statement answers these two questions: "What is the appliance not doing that it should be doing?" and/or "What is the appliance doing that it shouldn't be doing?" It doesn't go b
Manufacturers do sometimes help us techs out -- Samsung has been putting on training sessions pretty regularly both for their own models, and for Dacor-branded models as well (Samsung acquired Dacor a few years back, for those who don't know). While a lot of how we troubleshoot is by understanding the principles that are common to all appliances, you always need a bit of info specific to the appliance you're working on. In particular, information about the exact implementation of the technology
How you go about your troubleshooting makes all the difference between whether you're a Parts-Changing Monkey or a real appliance repair technician. While parts-changers rely on pattern recognition and rote memorization of "if this problem, then that part", a real tech uses analytical troubleshooting techniques and understanding of the technology involved to get to the right problem every time.
That's exactly what this excerpt from one of our technical training webinar recordings demonstrat
In the appliance repair world, we deal with two different kinds of thermistors: NTC (Negative Temperature Coefficient) and PTC (Positive Temperature Coefficient). Don't know what those terms mean? Don't worry, I'll break it down for you.
Despite both being thermistors, the only real similarity between NTCs and PTCs is that the resistance of both changes in response to temperature. Beyond that, they work quite differently and serve very different functions.
Here's what a typical NTC the
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