In this journey to Total Appliance Enlightenment™ in a Live Dojo workshop, we worked on a real-world problem on a Kitchenaid refrigerator posted at Appliantology. We were interested in how the defrost timer motor gets Line and Neutral in both defrost and run modes. Turns out that doing so required that we also understand the rest of the circuit, including the dumbed "PC board". But how do we do that? That's exactly what we show you in this workshop recording!
In this short little half hour
Many modern appliances use a computer to control the various loads in the appliance. But computers are also used for temperature monitoring and sensing. Typical temperature sensors used in modern appliances are NTC thermistors (refrigerators, dryers, washers, dishwashers) and RTDs (resistive temperature devices--used in ovens). If you're a member here at Appliantology, you can watch this webinar recording on Appliance Temperature Sensing Devices & Technology for a deep dive into how the comp
The lowly and dirty centrifugal switch mounted on the motor gets little love and attention. Always taken for granted and ignored and never respected.
But without the centrifugal switch, to take the start winding out of the circuit once the rotor gets spinning from a dead stop, the motor will draw high amps and kick out on internal thermal overload protection.
Well, boys and girls, in this exciting episode of Appliantology TV, we're going to see the mighty centrifugal switch in action
Y'all grab a cold one and gather 'round-- crusty ol' Samurai's gonna tell you a story. This here's a story about one o' them old skool dishwashers like yo momma had when you were still but a glimmer in yo pappy's eye.
These old skool dishwashers didn't have a separate, dinky little drain pump motor like today's gelded dishwashers. Nawsir, these old skool dishwashers had just one big honkin' motor that did double duty washing (more like sandblasting) the dishes and draining the basin. They d
This video shows the essential skill that all competent appliance repair techs should have: using the schematic to identify and locate your physical test points on an appliance. This process goes on both inside our heads and with our hands. This is the high skill, high dollar part of our job and it's what distinguishes real technicians from parts changing monkeys. We're using the example of a dual fuel range but this essential skill applies to any appliance.
Learn appliance repair
Whenever you're dealing with a warm refrigerator problem, your first question to answer is, "Am I dealing with a failed sealed system or a control problem?" In other words, you need to half-split the problem between the sealed system and the controls (air movement, defrost system, temperature control, compressor start device, etc.). I'm going to talk about three ways to half-split warm refrigerator problems to either rule in or rule out the sealed system and the controls.
1. Frost pattern
It's tough for appliance techs today. Our biggest competition is from cheap replacement machines. The proliferation of pricey electronic boards in appliances (and their uncertain procurement these days) means that if you can't quickly do a slam-dunk diagnosis, you are at risk of losing customers and your profitability.
Meanwhile, electrical troubleshooting is largely a lost science. What exactly have we lost? The Old Skool troubleshooting techniques that us old timers learned way back. And
Problem: I'm on a gas dryer service call-- no heat complaint.
Solution: Using only my jumper wire at the main board, I proved a problem with the Neutral sense line from the motor and made the burner fire up.
Question: At what two points did I place my jumper wire to troubleshoot this problem?
Problem statement: Freezer (FC) at 0ºF. Refrigerator (RC) section is warm.
Tech's questions— help a brutha out:
How can we force defrost in the RC compartment? Explain your answer.
How can we make sure the RC fan is running? Explain your answer.
How do we make sure the compressor is running at full speed? Explain your answer.
How do you explain the high temps in the RC?
(For you computer virgins, you can mouse over the schematic and click for a larger vi
You arrive on the call for Thermador wall oven. Complaint: F34 error code-- cooling fan rotation problem-- shown on the display when the oven is turned on. As a black belt in the martial art of schematic-fu, you pull up the schematic on your tablet computer. With one simple move, you identify the exact cause of the problem with ZERO disassembly.
Question: What slick move did you make to identify the specific cause of the problem with ZERO disassembly?
1. Which wires are the power supply circuit for the damper motor?
2. What does that switch by the damper motor do?
3. What's with the line going from one side of the switch back to the board?
Hint: This is a dead simple circuit. The motor does not reverse direction of rotation. The schematic alone tells you everything you need to know. You do not need any additional “inside baseball.”
Don't let me down, comrades. First one to answer all three questions correctly w
Hint: Please don't bore us with any amateur hour "ohm out" answers.
Extra credit: What is the function of the brown wire at pin 5 of the ADC controller?
Double extra-special credit: Enroll at Master Samurai Tech and a get free premium tech membership here at Appliantology.
First person to post the correct BEST answer, I'll hoist a mug of my flavorite brew in your honor. AND if you get the Extra Credit question, too, you'll get an electronic plate of my special cardboard c
"Happy Independence Day" from Team Samurai!
This Independence Day we invite you to declare your independence from the tyranny that enslaves so many techs.
What is this tyranny? Well, it comes in many forms, including:
Believing tech myths about circuits and technology, often without even realizing it.
Not being able to read a schematic, and so relying on others to give you troubleshooting advice.
Listening to parts-changing monkeys (PCMs) give bad t
We get asked this frequently by people who are new to the trade and considering enrolling in the online appliance repair training at the Master Samurai Tech Academy.
It makes some sense, as the appliance repair trade involves physical work, and any good repair tech will need to be adept at disassembly, performing electrical measurements, and replacing the parts.
But here’s the reality: training is a “brains-on” activity, which then is followed by hands-on practice.
You can get thi
Most techs today work by the philosophy of "tear down first, use the meter later." They claim that this is "old school. I'm old school and I'm here to tell you that is absolute BS.
Let's take an all-too common, simple example: dryer keeps blowing the TCO. I can't tell you the number of techs I hear talk about disassembling the dryer, replacing the TCO, only to have it blow again soon after. And they have no idea what's going on or how to even troubleshoot this problem. As an old school tech
Many professional appliance techs do not currently offer refrigerator sealed system repairs but are thinking about adding it to their service repertoire. In this post, I’ll offer some thoughts to help you decide if this makes sense for your service area. I'll also offer some resources for learning sealed system repair if you decide that makes sense for you. I encourage any of my Brethren in the Craft to post their comments and experience.
The false mystique of sealed system repair
Fi
Had some good questions at the webinar on the Bi-Directional PSC drive motor system used in Whirlpool VM washers. Professional Appliantologist members can grab some popcorn and watch the webinar recording here: Bi-directional PSC Drive Motor Systems in Whirlpool VM Washers
During the webinar, Joe asked how triacs are turned off. I wanted to give a more complete and accurate answer in this post.
To understand how triacs are turned off once they're turned on (and conducting) we need to