One of the first things you need when you start working on an appliance is the model number. Otherwise, unless there's a tech sheet with the machine, there's no way to find technical info on it. But what do you do when the model number tag has been damaged or removed? It's a rare occurrence, but one that can cause a major roadblock in a repair. Here's an example of one such situation:
As you can see, both the model and serial numbers are almost entirely illegible. Fortunately, there's
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
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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See if you can identify two things on this Samsung dishwasher schematic:
1. Where does the control board receive line and neutral?
2. Where do the sub-control boards get their DC power supply?
The answer to the first question can be found easily enough, if you have a little schematic reading experience. But it's a bit trickier for those who don't have as much practice.
For one thing, line and neutral aren't explicitly labeled. Just wire colors are given, but fortunately
Take a look at this LG gas dryer schematic, paying special attention to the circuit with the flame detector.
If you trace it out, it becomes a bit puzzling what that circuit is actually doing. The hi-limit thermostat, the safety thermostat, and the flame detector don’t appear to have any direct effect on the gas valve coils as you would find in other dryers. So what purpose do they serve?
This markup makes it all clear.
Unlike many circuits that use controls li
Ever looked at a timing chart and been mystified by how to decipher it? Or maybe you're looking at the schematic, and you can't make heads or tails of which switch is supposed to be closed when during a cycle.
If timer charts have ever given you trouble, then this is the video for you. In less than 10 minutes, we'll show you how to read a timer chart, correlating it with the actual steps of the cycle, and then identifying how it relates to the state of the switches on the schematic. Give it
Jazz boards are a classic common-fail item in Whirlpool refrigerators, so important to know the right way to go about troubleshooting them. The good news is that they operate on the same principles that all control boards do, so if you know your basic electricity and troubleshooting principles, making big money off of these is a snap.
This is exactly the kind of stuff we teach in our Core Appliance Repair Training Course over at the Master Samurai Tech Academy. If you want a taste of that g
Every split-phase motor needs a start device, and split-phase compressors are no exception. There are a variety of start devices out there for compressors, and it's vital for your troubleshooting that you understand how they work. In this short excerpt from a longer webinar recording, the Samurai steps through the differences between relays and PTCs, laying the groundwork for differentiating between these devices in the field.
If you want to learn more about the technology used in modern re
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 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
Is there a reason to distinguish ground from neutral when it comes to electrical testing? If you need a reference for a voltage measurement, doesn't ground work just as well as neutral?
Not at all! Ground and neutral are supposed to be two separate things in an AC circuit, and so they can't be used interchangeably. In this short webinar excerpt, the Samurai breaks down what the difference is and why you should only ever use neutral in your AC voltage measurements.
The full version of t
Picture it.
You're walking into the service call of a long day, but you're feeling good. You've got your tools in hand, you've done all the prediagnosis; you're gonna kill it. The customer lets you in, and while chatting affably he begins leading you to the appliance.
You can't place why, but a dark cloud of foreboding passes over you. You push it aside, but the feeling only grows. He's leading you downstairs now, into the basement. It's dingy down here -- clutter everywhere.
No,
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) --
For those of us techs based in the States, it can be easy to think that electricity just "happens to exist" as our familiar 120/240 volt split-phase power. But that's only one of many forms that electrical power can take. It can come in a variety of voltages and phases, all depending on what standard a particular country or region decided upon.
Let's step through the most common of these. There are two that North American techs are likely to encounter: the typical 120/240 volt split-phase t
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
Vent hoods are pretty simple appliances -- something you've probably surmised if you've ever looked at the schematic for one. Usually, all they have going on is a blower motor and a couple of lights. When it comes to troubleshooting a hood, there are just two technology-related concepts you need to be familiar with: venting specifications and how multi-speed motors work.
First, venting specs. As with any machine that produces exhaust as part of its operation, vent hoods have certain require
You open up the terminal block on a Bosch range, and you see this. What's wrong with this picture? (Hint: those of you who have watched this webinar recording should know what's up).
A few questions for you sharp Appliantology techs:
Will the machine run in this configuration?
Why is it not okay to leave the machine in this configuration?
Does this machine have a 3 or 4 wire power cord?
How would you correct this situation?
Let me know your answers
Information has always been the name of the game for appliance repair techs. Our jobs are all about locating and making extrapolations upon information such as specifications and measurements. If we can't access at least a baseline level of information for a particular job (at the very least the schematic), then it's almost impossible for us to do our job.
The meteoric rise of mobile technology and the Internet over the past few decades has hugely expanded how much information we can access
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
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
Both of the big Korean manufacturers -- LG and Samsung -- have a little trick that they like to use in their schematics. While I think they do it to keep the lines from becoming too much of a tangled mess, it can sometimes be a bit unclear for the uninitiated. Here's an example of an LG refrigerator schematic:
The whole picture is a bit much, but notice all those bubbles popping up around the schematic? Let's pick one of those and focus in on it. Here's one coming off the sub PCB:
Have you ever been robbed of a quick troubleshoot by ghost voltage? How about by an open neutral? Sounds like you need to start using a loading meter for ALL of your AC voltage measurements. Watch the video below to learn why, and find out some things you didn't know about circuits and electrical measurements along the way.
Want to see the full troubleshoot of this dryer, showcasing multiple ingenious voltage test locations that ensure for a fast and accurate diagnosis? Click here to watch
All of us techs are carrying around multimeters these days, and that means we have several different voltage measurement settings available to us at any given time. Usually these are DC voltage, AC voltage, and LoZ (low input impedance). Each of these functions has a specific use, and part of taking a voltage measurement is picking the correct setting for the job.
LoZ is by far the most common voltage function you should be using. In fact, there is almost never a time when you should do an
Here's the situation: the tech has a Maytag dishwasher with no lights, no life, no nothin'.
With a multimeter on LoZ, the tech has already checked the following with reference to ground. Here are his findings that he reported:
Seeing that there was a solid 120 volts to the board and no operation, the tech concluded (with the aid of a few ohm checks across the control board) that the board was the culprit. He replaced it, and...
Still nada.
How could such a seeming slam-dunk
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