A tech here in the Appliantology forums ran into a surprising customer complaint about a microwave: it's doing its job too well! They say that it's cooking food way faster and way hotter than it used to.
(The above picture is a slight dramatization.)
So, our tech took a reasonable step and measured the amps going to the microwave. After all, if the magnetron is producing more watts than expected, it will have to be drawing more amps.
Measuring Power Consumption
His meas
Let's take a look at the interlock switches in a Kitchenaid microwave-oven combo unit with a simple question to answer: which of the microwave interlock switches should be closed when the door is closed, and which should be open?
Here's the schematic for this model with the switches in question circled:
Should be simple enough to find the answer to our question. In fact, most schematics worth their salt tell you the state the unit is in as shown. Ours has just such a note:
Bimetals show up all over the appliance world in all kinds of applications. Resistive Temperature Devices (RTDs) are widely used in ovens and ranges and are commonly called "oven temperature sensors." Both are devices that respond to temperature, but beyond that, they work completely differently and serve different purposes. Watch this short excerpt from one of our many technical education webinar recordings to learn all about these devices!
The full webinar covers all the common
What do you do when even the service manual can't be trusted?
In this video, we discuss how to deal with bad or missing information in all kinds of tech docs -- service manuals, tech sheets, schematics, you name it. Topics covered include:
Pin numbering discrepancies
Reconciling pinouts with schematics
Identifying power supplies
Recognizing incoherent specs
What are dummy directions?
..and more!
You can watch this one right now for free! We've
We had an interesting discussion at our most recent Live Dojo workshop! This dryer only runs when the push-to-start button is held down -- a relatively simple problem, but troubleshooting it requires us to understand the entire motor circuit and how it works on startup.
We began by using Ten-Step Tango to orient our troubleshooting, identifying our Load of Interest and analyzing its circuit.
This led us to examining how the start switch works, which includes some interesting components
DC power in appliances works the same way no matter the manufacturer, but everyone has their own way they like to talk about it. And if you're not up on the lingo, you'll be left mystified by DC circuits in schematics.
You don't have to worry, though, because we explain all kinds of DC terminology in this latest workshop. From VDC to VCC, we cover everything you're likely to encounter in your troubleshooting travels through DC power, including:
Terms for DC voltage supplies
T
In this clip from a longer webinar, we give you the long and short of how NTC thermistors work and how to troubleshoot them. Don't know what NTC means? Don't worry -- that's covered in this video, too!
Want to watch the full webinar, which goes through using the Samurai's Troubleshooting Ten-Step Tango to nail refrigerator problems every time? Click below -- viewable only by premium members.
All appliance repair techs should understand the AC split-phase household electrical power supply that they deal with on a daily basis. But the fact is that most do not, and there's a lot of disinformation and "tech myths" out there about these power supplies. But they re easy to understand once you grasp a few fundamental concepts about electricity and split-phase voltage.
And that's exactly what we cover in this webinar recording!
Topics covered include:
How sine waves are us
Schematics and wiring diagrams -- two different kinds of service documents that seem similar, but actually serve completely different purposes. One of them is essential to any electrical troubleshooting and should be consulted on every service call, while the other has much more niche applications. But which is which, and how do you tell them apart?
That's what we explore in this workshop, which is an excerpt of the discussion from one of our latest Live Dojo workshops. In it, we go through
These aren't your grandma's ignition systems -- these are systems that use a DSI (Direct Spark Ignition) board, and that means you've got algorithms involved.
If you want to troubleshoot a DSI system, you need to understand this algorithm -- it's how the board thinks. Is the DSI board not sending any voltage to the electrodes? Well, it might just be in lockout mode after a failed ignition, meaning the problem lies elsewhere than the board. You can't troubleshoot a system if you don't know h
When it comes to switches in appliances, it's hard to think of one more ubiquitous than the relay. It can be used with and without a control board, and it allows a small voltage to control a much larger voltage. But what exactly does that mean, and how do they do that? And what about triacs, the relay's solid-state cousin?
We cover both of these devices, including how they work and how to troubleshoot them, in detail in this excerpt from one of our recent Live Dojo workshops. Give it a watc
There are a lot of funky things going on on this Electrolux dishwasher schematic -- including normal-looking switches that are labelled "transistor switches". What does this label mean, exactly, and how does it affect our troubleshooting? That's what the Samurai breaks down in this short clip from a longer technical webinar recording.
Want to watch the full webinar? Click below to watch -- available only to premium members.
Take a look at the defrost circuit on this Whirlpool refrigerator:
Looks pretty standard -- there's just a defrost heater and a defrost terminator in the circuit, and voltage is supplied to the circuit by the control board.
But what is the purpose of the wire marked in green that tags off to J1-3?
If you look closely, you'll see that that pin on the control is labeled D-SENSE -- so that's a sensing line. This means that the purpose of that wire is to give the control board i
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
More than any other AC load, motors are all about amps.
What do I mean by that? When you have a motor that is misbehaving, the best, most informative electrical test you can do by far is amps. And one of the worst mistakes you could make is to just rely on ohms when testing a motor.
In this recording from one of our biweekly Live Dojo workshops, we go over several different aspects of troubleshooting motors.
Thermal controls are the first order of business. All AC motors have an i
We had some fun in this Live Dojo Workshop! We went beyond the screen into the big, scary Real World and showed off live a few things about BLDC fan motors, including:
BLDC fan motor wire color conventions
Expected readings on PWM and RPM feedback lines
Simulating a PWM signal
Identifying failed speed sensor
...and more! Click below to watch the workshop recording -- viewable only by premium tech members.
If you're an Appliantology tech member and y
How are we as techs supposed to understand the specifications we see on a split-phase motor's label? What's the difference between a motor's output power and its input power, and which of those specs is given on the label? What do acronyms like FLA and LRA mean? All that and more covered in this short video on motor specifications.
This is just a short excerpt from the great technical discussions we have every other Saturday during our Live Dojo Workshops. If you're not joining us for these
More and more folks are doing online training webinars these days -- so many, in fact, that it can be impossible to keep up with them all. Recently, Samsung and MSA both put out training webinars on Samsung dishwasher technology and troubleshooting, and I figured I would share the love with the Appliantology Brethren.
In the links below, you'll find my notes and screenshots from both webinars. Topics include:
Troubleshooting the OC/OE error
Identifying common sources of leaks
Be warned: this week's troubleshooting scenario is somewhat chilling...
...or maybe not, since the problem is that the ice dispenser isn't working. In fact, the entire fridge shuts down when the ice dispenser is activated. How can this be? Well, in this recording from one of our biweekly Live Dojo workshops, we go over the relatively simple cause to this strange issue.
Loading down is the culprit here. That's when a faulty load grounds out the control board's DC power supply, causing a
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.
I wanted to highlight a recent topic in the Appliantology forums because it showcases a few good teaching points -- and because it had some fun pictures.
Here's the initial setup that the OP gave in his post about an electric dryer:
There's a very important tidbit in there: someone other than the tech did work on this previously. Maybe another tech, maybe the customer -- we don't know. We'll circle back to why that's so important.
The OP continued:
So, over the course of
A tech here in the Appliance Repair Tech Help forum recently ran into a conundrum: the range he was working on had an open bake valve, but there was also no voltage going to either the bake or the broil valve from the DSI control board. So is this just an issue with that open valve, or does the board need to be replaced as well?
To find our answer, let's first look at the schematic for this range.
Circled, from left to right, are the bake and broil relays, the bake and broil valv
You would think that there wouldn't be a lot going on with an oven's convection fan motor -- and you would be wrong! This Viking convection fan has a number of interesting elements in its circuit that we're going to explore in this post.
1. Is that a 240 VAC power supply for a fan motor? Turns out that you can actually run a fan on 240 VAC if you want to (and if the fan has the proper specs for it). There are even certain benefits to doing so.
2. Not just one, but two capacitors in the
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
You don't have to be a physicist or a mathematician to troubleshoot properly, but you can't get around the fact that math is the only way to really understand electricity. Sine waves are one such mathematical representation used for both voltage and current. But how does this representation work, exactly, and how does it help us wrap our head around voltage, current, and power?
That's what we'll break down for you in this excerpt from one of our many full-length technical webinar recordings
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