How a Real Tech Prepares for a Service Call

A thorough pre-diagnosis improves first call completes

By Sam Brown, Master Samurai Tech/

At Appliantology, our primary mission is to support appliance repair techs in performing pre-diagnosis. That is, the method of doing as much troubleshooting as you possibly can before setting foot in the customer’s home.

Pre-diagnosis is the biggest factor in increasing FCC (first call complete) rates, and the higher the FCC rate, the higher your company’s profitability.

So how exactly does one pre-diagnose, and how does Appliantology help with that? Well, let’s walk through the journey of an Appliantology member pre-diagnosing a service call.

Step 1: Collect the model number and customer complaint.

This is something you should already be doing for all your service calls. Once you’ve got these two pieces of information, you then need to verify that the model number is valid, and then boil down the customer’s problem complaint into an actual problem statement.

A problem statement is not what the customer thinks is wrong with the machine, nor is it your “best guess” at the problem. This is just you taking what the customer tells you and distilling that into a statement of what the machine is doing that it shouldn’t be doing, and/or what the machine is not doing that it should be. It’s as simple as that.

Step 2: Look up the tech docs for your model in Appliantology’s Downloads section.

Now that you have the model number, it’s time to find the tech sheet or service manual for your machine. And yes, we’re doing this right now, well before you drive out to the service call. Why? Because we’re putting together a game plan.

Normally, finding technical docs on the Internet can be a pain, especially for certain manufacturers. Here’s where Appliantology comes in. All you need to do is plug your model number into the search bar in the upper right corner of the site and see what comes up. Make sure to select “Files” in the dropdown menu if you’re looking for manuals.

We have a massive and constantly growing selection of technical docs for all major U.S. manufacturers, so more than likely you’ll find what you’re looking for. And if you don’t? No worries. That’s exactly what our Service Manual Requests forum is for. Any premium member of Appliantology can request a manual there, and we’ll track it down for them.

Step 3: Perform your schematic analysis and form your troubleshooting plan.

Now that we have our info, it’s time to use it. Before we even think about getting in the service vehicle, we’re going to figure out what load we’re going to be focusing on — our “Load of Interest” (LOI). If there are multiple “in-operable” loads, select any of them as your LOI and work the problem; you’ll usually end up at the same root cause. Then we’re going to do a thorough schematic analysis of the circuits associated with those loads, as well as generally reviewing other useful information about the machine, such as error codes and diagnostic modes.

Shaky on how to use a schematic to form a troubleshooting plan? Appliantology has your back there too. We have almost 100 hours of in-depth technical training videos on-demand for our premium members. These are all our own original content, so you’re not going to find them outside of Appliantology or Master Samurai Tech, our training site.

You can even search for past topics that other techs have started for similar problems, using the same search bar you used to find tech docs. Maybe someone has encountered something similar in the past and has some wisdom for you.

Step 5: Git ‘er done!

Now you’re fully equipped for the service call. You’ve studied the circuits, formulated your theory of the most likely causes of the problem and figured out how you’re going to go about troubleshooting them. That’s a lot of work that you don’t have to do while the customer is looking over your shoulder. And trust me, you’ll feel the difference immediately, as will your bottom line.

Want to join the Appliantology community and start pre-diagnosing like a pro? Click here to become a member today.

Sam Brown is “Professor of Appliance Repair Mastery” at BrandSource partner (MST), an online training academy for appliance repair personnel, and is the administrator of its sister tech support site, For more information, email Sam at or call (603) 290-5516.

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