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Let's take a look at the sine wave you would see if you hooked up an oscilloscope to a typical household power supply. This is showing reading line with respect to neutral.
Hopefully you're already familiar with using a sine wave to represent AC voltage like this. To define a little terminology: the peak voltage (shown in green) is the voltage difference between the middle line (0 VAC) and the highest point of each peak. This diagram shows 170 VAC peak. Peak to peak voltage, on the ot
Let's take a look at a multimeter and talk about what each function does and what it's good for. This is specifically for a Fluke 116 multimeter, so if you have a different meter, you might see a slightly different array of functions. But this will be representative of a typical multimeter.
LoZ: That stands for "low impedance". This is the loading function of your meter, meaning that it allows you to do voltage measurements that actually put a load on the circuit, allowing for a small
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
Take a look at the cooktop schematic below.
I don't know about you, but "tranformator" isn't a familiar term to me. it certainly sounds like a transformer, but why would a transformer be necessary in a 240 VAC cooktop element circuit?
The best thing to do here is to look up the part numbers for the "transformator" as well as other key components, such as those cooktop switches that the transformator is supplying power to. Then we can use a parts site to look at physical pictures
Internet-connected appliances aren't a niche anymore. They're made by just about every brand out there, from Samsung to Whirlpool and beyond, so if you want to stay in the appliance repair game, you've got to know how they work. Lucky for you, this post is going to break down what you need to know to work on them.
The key thing to keep in mind is this: internet-connected appliances are not that much more complicated than normal appliances. As long as you grasp a few fundamental concepts, th
Have you ever noticed some connections on a schematic that just look plain unnecessary? Take a look at CN1 on this diagram.
If you trace out those three wires, it may not be immediately obvious to you what the point of them is. Let's look at each connection individually, starting with pin 1.
Well that looks pretty standard. It takes a direct path to neutral with no components in between. Nothing unusual about that -- the board needs its own neutral supply in order to run, a
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
PSC (Permanent Split Capacitor) motors are nifty pieces of technology that you'll most often encounter in Whirlpool's VWM washers. They operate a bit differently from your typical split-phase motors. Rather than having a dedicated start winding and run winding, with each winding having different specifications, PSC motors have two windings that are physically identical. The only difference between them is in what direction the windings are wound.
Another big difference between PSC motors an
New technologies are never invented specifically for household appliances. We always get hand-me-downs. But just because a technology was used first in a different field doesn't mean that we're familiar with it already when it reaches appliances.
TMR (tunnel magentoresistance) sensors are one such example. Coming to us from the world of computer electronics, they serve the same purpose as Hall Effect sensors but work completely differently.
A TMR sensor consists of two ferromagnets sep
Here's a timing chart and a schematic. See if you can spot the problem... (HINT: it's in the motor circuit.)
Did you see it? If you did, bravo! Your schematic-reading skills are pretty sharp. If not, don't worry -- I'll step you through it.
Like I said, the error in the schematic is in the motor circuit -- specifically the start winding. Like any good tech, I'm going to do a load analysis on that winding to see what's up.
Line and neutral both have to go through
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
With the ongoing COVID-19 crisis, things are changing quickly. No matter how long or short the actual pandemic lasts, everything won't just go back to how it used to be, and if we appliance repair techs want to stay in business, we will have to adapt.
What exactly that adaptation looks like remains to be seen, but Team Samurai has been in the business long enough to have some solid ideas about it. Heavy sanitation precautions are something that is already happening and will continue to beco
If you cracked open a freezer and saw the defrost drain looking like this, what would be your immediate reaction?
Do you see what the problem is? Take a closer look...
Have you figured it out? The deal with this defrost drain is...
There is no problem. This is a clear, perfectly normal-looking defrost drain. You can see a little evidence of some water pooling and freezing, but the amount is well within acceptable limits. Based on a visual inspection, there is no issue
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
How would you go about troubleshooting the valves?
As always, we should start with a load analysis on your load (or in this case, loads) of interest. That means identifying how each valve gets line and neutral. (The wire marked with a blue N connects directly to neutral).
You should immediately see that something is off. How do the IM and water valves get neutral?
The answer is that someone over at Whirlpool made a whoopsie when drawing this schematic. There should be a line
Here's something you don't see every day: a gas range that is powered only by a 9 volt battery. Pretty nifty, huh? @Littletexan told us about his encounter with this one in this post from a couple weeks ago.
Let's look at some of the unique aspects of this model. We'll start, as always, with the schematic:
Well that's about as simple as it gets! All mechanical controls -- nothing too fancy going on here.
One thing I will point out is that, while the schematic seems to show a
@LearningTech dropped a great tip in The Dojo a little while back: not all LG control boards can be updated after a universal compressor is installed. If you're planning on doing sealed system work on these machines, you're going to want to check the list below to see if your model's PCB can be updated. Otherwise, you might be in for a nasty surprise.
LearningTech also provided a handy image showing where you can find a PCB's manufacturing date:
Want to be in on cool tech t
Most of you have probably heard about loading down before -- when one failed DC component causes a ripple effect that keeps other DC components from functioning properly until the failed component is removed. But what does that actually look like in practice? And how do you go about troubleshooting it?
To answer these questions, let's take a look at a straightforward, real-world example of loading down (taken straight from this topic at Appliantology).
@marshall450 ran into what seemed
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
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
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
Didn't make it to ASTI this year? You missed out on some great technical info!
But don't worry -- we took careful note of all the juicy tech tips being dropped by Samsung, Bosch, and Whirlpool in their technical training and showcased them for your benefit in this latest webinar recording. Give it a watch to get the inside scoop!
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
During the second half of my stay at ASTI 2020, I got the chance to get the inside scoop on Bosch dishwashers and many different kinds of Beko appliances. While the Bosch training didn't have much new to say, I got a pretty good look at the nuances of Beko products. They've got some nifty features that I haven't seen elsewhere, but there are some quirks to their design and documentation that could make for difficulties with repairs.
Take a look at my notes and see for yourself! Available to
Just got back last week from ASTI 2020 in (not so sunny) Florida! Aside from helping man the Master Samurai Tech booth at the trade show, I attended as many of the manufacturer training sessions as I could. I figured some of the Appliantology Brethren would like to take a peek at my notes...
The first day and a half, I sat in on Liebherr, Samsung, and Whirlpool training. While these manufacturers all generally focus too much on monkey training (disassembly and other information you can easi
By Son of Samurai in Appliance Repair Tech Tips2 comments
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