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
Techs as a community have developed some bits of jargon that serve as shorthand ways of describing specific technical situations. These phrases are useful for saving ourselves time and breath, but sometimes the exact definitions get blurry. Even worse, sometimes the way that the phrase sounds gets confused for a description of the actual science/physics behind what's going on, leading to a variety of "tech myths". Let's clear up a few of these terms.
"Failing under load"
This a situat
When it comes time to perform the repair and install a new part, the last thing you want is a surprise throwing a wrench in your plans. All the unexpected twists and turns should have already been dealt with during your troubleshooting. Ideally, performing the repair itself should just mean doing as little disassembly as possible, installing the new part, and collecting your repair fee.
While there will always be unforeseen problems every now and then, there are a couple rules of thumb to a
Here's a weird one for you: how does this dryer run with the neutral wire of the pigtail completely disconnected? To find out, watch this short, 7-minute excerpt from one of our many full-length technical training webinar recordings.
In this video, you'll learn the answer to questions like:
What is the difference between 3 and 4 wire dryer cords?
Why should neutral and ground be separated?
Why is the dryer able to run without neutral connected?
Give it a watch a
We've got a tricky one for you today: a Frigidaire-built Kenmore electric dryer that only runs on heat cycles. If you set it to a timed or auto dry, it runs just fine. But set it to air fluff, and you get nada -- no motor rotation, no nothin'. Sounds like a bad timer, right? That was our first thought, too. But like any good tech should, we covered all of our bases before jumping to conclusions, and what we found was much more interesting...
We'll start by analyzing the circuit of the motor
When you need to test a component, do you always need to just resign yourself to tearing apart the appliance until you reach it? Or is that a waste of time and energy (not to mention unnecessary liability), when you could be working smarter, not harder?
Let's say you're working on a Samsung dryer, and you want to measure the thermistor. You know the ohm spec (unfortunately they don't give you voltage drop), so all you need to do is get your meter probes on it so that you can compare. Is you
Self-clean sounds like a great idea, right? Just push a button and watch your oven burn away all that caked-on grease and charred food.It certainly makes for a good selling point. But is this no-hassle cleaning feature really all it's cracked up to be? And what is the best way for the customer to use it (if at all)?
First off: does it actually work? Can the oven clean itself just by getting really hot? Yes, definitely. Self-cleaning isn't just a gimmick, and when used properly, it does actu
Reading schematics is an essential part of troubleshooting, but it's not always clear how to break down a circuit into understandable bits. Is there an easy rule of thumb for identifying what component does what and how to go about testing it?
In this excerpt from one of our many full-length technical training webinar recordings, you'll learn exactly that! In addition, we'll show you how to break down a seemingly tangled schematic and identify loads in series vs. loads in parallel -- all in
Did you miss our awesome webinar a few weeks ago? With all the computer-controlled dryers out there today, many techs forget that they still need Old Skool circuit troubleshooting skills to solve many dryer problems they'll encounter in the field today. With that in mind, our recent webinar covered four real-world dryer case studies on simple dryer circuits that trip up lots of techs who should know better (and think they do but, in fact, do not).
Some of the topics we covered include:
By now, most of us are used to variable speed drive motor systems in appliances. The control board sends a PWM signal to an inverter, which tells the inverter how fast to run the BLDC motor.
While this is the type of inverter that's been used in appliances for years now, it's not the only kind of inverter out there. In fact, another type of inverter is starting to crop up in the appliance world, and it may very well become the norm for some applications. It's called a drop-in inverter, and
"Ohms lie." It's become a popular phrase in the tech community, but what does it actually mean? Should you never do an ohms measurement? Are they completely worthless? Or is this phrase just another example of tech mythology?
The answer is more complicated than any of that. Let's run through a quick example to demonstrate. This is an old-skool Whirlpool gas dryer, just like they were cranking out left and right in the good old days.
Now, our scenario is a simple one: when we run
In this excerpt from one of the many technical training webinar recordings available to our members, we cover two tricky areas that have tripped up many a tech: deciphering an unclear schematic, and decoding a convoluted customer problem description. Both of these are essential skills for any tech, since if you mess up either of these steps, the entire rest of your troubleshooting will be thrown out of whack.
The troubleshooting framework that we're using in this video is our patented Ten-S
Put simply, diodes are devices that only allow current to flow in one direction. In DC circuits, this means that a diode can either act as a conductor, just as a stretch of wire would, or as an open in the circuit, depending on the configuration. See the examples of DC circuits with diodes below:
That arrowhead-like symbol is the diode. The fat end of the arrow is the positively charged anode, while the narrow end that meets the straight line is the negatively charged cathode.
Fi
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
Special guest presenter Mark Williams will show you how easy it is to diagnose temperature problems in the newer electronically-controlled refrigerators and how to do it right the first time.
We'll show you examples from Samsung, LG, GE, Whirlpool, and Electrolux. You'll see that they all work the same way.
You'll also see how to accurately test thermistors from the computer control board and you’ll learn the difference between resistance and voltage drop when it comes to testing the
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
Samsung has developed something of a reputation in the tech community, and not necessarily the most flattering one. Many consider the brand to be overly-complicated and impossible to troubleshoot, and some refuse to work on these machines at all. But is this attitude really warranted?
All appliances everywhere work on the same principles, and Samsung is no exception. The idea that Korean appliances like Samsung and LG somehow work differently is pure mythology, and this short excerpt from o
Sometimes, manufacturers don't write out schematics as clearly as they should. In cases like this Frigidaire cooktop, the way that the relays for the simmer function are drawn is downright obtuse.
In our latest workshop webinar, we broke down the function of this circuit and really understand how it works, bringing our electrical and technical know-how to bear to make logical deductions about the circuit.
Did you miss the original webinar and want to watch this webinar recording? Click
Imagine you're in this situation: you're trying to do some ohms testing on the heater of an LG electric dryer. You're reading 21 ohms across a single coil, and 42 ohms through both coils. But when you look at the spec on the schematic, you're seeing almost exactly half that:
Weird. Maybe the heater is out of spec, but that's a weird discrepancy. And it's bizarre that we're reading double the specs given.
Can we get a second opinion? You look elsewhere in the manual, and you find
Many techs are intimidated when it comes to troubleshooting control boards. After all, we're talking about computers here -- computers that just so happen to run appliances. But as complicated as that may sound, control board troubleshooting really boils down to just three things: measuring your inputs, measuring your outputs, and understanding the board's algorithm.
Let's start with inputs. Input just means anything, be it a power supply or some information, that the board receives f
We had a great webinar this past Sunday all about troubleshooting a Thermador wall oven with a cooling fan that wouldn't run. Lots of vital tech know-how covered in this one, like how to structure your troubleshooting flow, identify loads and switches on schematics, and perform useful and meaningful tests that will lead you to the correct solution.
In this short excerpt from the recording of that webinar, we talk about using the schematic to identify EEPs for your testing -- no unnecessary
Here's something for you sharp Appliantology techs to puzzle over: what in the world is the circled symbol on this schematic?
Is that a wiring harness? Maybe this diagram's strange way of showing a splice?
To figure out what it is, we've got to have a functional understanding of how Electrolux likes to design their water valve circuits. Let's look at a similar configuration that's drawn differently.
There we have it -- on this schematic, the engineers decided to throw
When it comes to troubleshooting BLDC motors and inverters, there's usually a standard strategy. You check the input to the inverter (a good 120 VAC power supply and a PWM signal from the main control) and you make sure the motor windings are in spec and all the same resistance. But what about measuring the output of the inverter?
This is certainly possible to do, and it can be a useful measurement, especially in hairier inverter troubleshooting scenarios. But before we get into that, let's
Want to really put your technical know-how to the test? Well, have we got the webinar for you!
This one covers a whole potpourri of circuit puzzles and troubleshooting scenarios, including:
Some pop quizzes about series and parallel circuits
Diodes, how they work, and the surprisingly tricky situations that can arise because of them
Loads in series, how they work, and what they look like in a real refrigerator schematic
A real world troubleshooting scenario invo
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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