There's a goal that any tech worth his salt should have when he heads into a service call: troubleshoot the machine until he has logically and definitively located the problem.
Most of the time this goal is achievable, as long as you have the documentation for the appliance you're working on. You can take measurements and compare them with the specifications from the manufacturer until you find what's not within specifications. This is called analytical troubleshooting and is, in fact, the
Loading down is a failure scenario unique to DC power supplies, and if you don't know what to look for, it can leave you scratching your head and eating some expensive parts. How do you identify that you have a potential loading down scenario, and what steps can you take to verify that? That's exactly what we cover in this Master Samurai Tech Workshop.
Topics covered include:
How DC power supplies work
How they affect the board's operation
What loading down is and how
In this webinar recording for the ages, the Samurai explains everything you need to know to run a successful service call, minimizing return trips and maximizing profits. He covers the steps you need to take before the call and how you need to think while on the call. All of this information is neatly and concisely presented as The Samurai System for Service Call Excellence -- a must-know for any tech who wants to make the most money for the least headache.
The topics covered include:
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
Sometimes, the hardest part of being a tech is dealing with the customer. Customers always have expectations, some reasonable and some not, and we have to manage these on top of performing our diagnostics and repairs.
A large part of being a real technician is knowing when to trust your own expertise over customer demands. This struggle generally manifests in two ways:
1. The customer has their own diagnosis that they're sure is correct. We've all encountered this before. Something alo
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
Take a look at this motor circuit:
Three different windings? Triacs in the circuit? A "sense resistor"? What's going on here?
As it turns out, there's nothing really new or different happening here. In fact, all we're looking at is a standard split-phase motor with two different start windings. One is the start winding when the motor functions as a drain pump, and the other is for when the motor functions as a wash pump.
Here's what the circuit looks like when the drain wind
Many techs are intimidated when they first look at a schematic -- but you don't have to be! You can make sense of any schematic, even one with multiple control boards, by following some simple troubleshooting principles. And that's what we're going to show you in this short clip from one of our many technical training webinar recordings.
In it, we'll use a real-world tech sheet to demonstrate some of these principles, such as:
Identifying the control boards
Identifying the b
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
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
Two of the most common circuit protection devices we'll see on outlets or circuit breakers are AFCIs and GFCIs. But what exactly are these devices, what do they do, and what are the differences between them?
The Samurai answers these questions in this short excerpt from one of the hugely enriching webinar recordings available here at Appliantology. Want to watch the full webinar and learn the whole scoop on these protection devices? Get access to it and 50+ hours of on-demand recordings by
We've got dozens of hours of webinar recordings here at Appliantology covering all kinds of appliance repair troubleshooting strategies and technologies, ranging from the very advanced to the fundamental. This short excerpt from one of our many recordings covers the basic, but crucial concepts you must understand to troubleshoot an appliance with a control board -- even on seemingly "weird" brands like Samsung --including:
How to read and troubleshoot with board pinouts
How do DC
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
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:
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.
When you see a term like "FlowSense" in a service manual, don't immediately assume that you're dealing with some bizarre, new technology. 99% of the time, it's just a fancy brand name that the manufacturer slapped on a bit of simple tech that's been around for decades.
And that's what you're going to see in this video! in it, we show how "FlowSense" is just a fancy name for a single sensing line on the control board that detects the presence or absence of L2. Watch it now to learn exactly
Volts, ohms, and amps -- these are the three types of electrical measurements from which we draw our diagnostic conclusions as appliance techs. They all have their uses, but watch out -- they're not all equal in usefulness or reliability! Let's go through them one at a time.
Ohms: Despite being a lot of techs' go-to measurement, ohms is actually the least reliable of the three. This is due in large part to the fact that it can only be performed on a dead circuit. This means that it complete
Tell me what's wrong with this picture:
No, your eyes are not playing tricks on you -- that schematic really is showing a split-phase compressor being run by an inverter board.
If you're sitting there sputtering and foaming at the mouth in disbelief, thinking, "That can't possibly be correct," then congrats! You had the correct reaction. What this diagram is showing simply can't line up with reality. Split-phase motors are never run using inverter boards -- the very idea is nonse
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
Our scenario today is a dryer that heats intermittently. Blitzing through the Ten-Step Tango, we select the heating element as our LOI.
But how do we test the heater's power supply? Do we have to start tearing things apart to do our tests?
If you've been around Appliantology long enough or taken our courses over at Master Samurai Tech, then you'll know that the answer is, of course, "no". Instead, we've just got to look at the schematic and pick some clever test points.
All
Come on a journey with me as we explore just how tangled your circuit analyses can get when you're confronted with conflicting information in a tech sheet.
Here's the Samsung washer schematic we're working with:
Nothing crazy here -- this is pretty standard stuff to see on a Samsung schematic. But when it gets weird is when you try to trace out the power supplies of various loads and board on the schematic with the help of the pinouts elsewhere in the same tech sheet.
Here's
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
Think you know your circuits? How about we put that to the test!
In this excerpt from one of our many illuminating webinar recordings, the Samurai traces out the circuit for a refrigerator evaporator fan. Interestingly, the neutral side of the fan's power supply goes through both the defrost terminator and the defrost heater. How can this be?
Watch this excerpt and ponder the mystery for yourself. When you think you have the answer, click here to view the full webinar and see if you go
When a control board doesn't seem to behave the way it's supposed to, does that mean it's always time to replace the board? How do you avoid the dreaded callbacks on service calls where you replaced the board because you had no idea what else to replace? Is there a way to reliably troubleshoot computer-controlled appliances and avoid guesswork when it comes to the control board?
Of course there is, and Team Samurai is going to show you how!
It all boils down to understanding how these
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
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