Damn! My toaster isn’t working. This pile of junk hasn’t worked properly ever since I upgraded it to tOS (toast OS) v8. Every time I tell it to lightly toast I get “burnt to a crisp”.Of course, we never really face these kinds of problems with our toaster. It really only does one thing - char the outside surface of bread products - and there isn’t all that much to fiddle with anyway.
A computer, on the other hand, is a far more general-purpose device with an infinitely greater scope for stuff to go wrong.
However, with some thinking and understanding you can develop processes that will help you fix any computer problem at all. Even if you’ve never seen it before and don’t really know why it’s happening.
What is this magic panacea for computer woes I hear you ask?
It’s called a diagnostic process.
At it’s heart is the concept of carrying out systematic troubleshooting.
Let’s take an example:
Your iMac can’t load any web pages.
(For this example, I’m also going to stipulate that we’re dealing with an ADSL connection…)
One approach to a repair is just to randomly try things and see if they work. For example, you might install Firefox instead of using Safari and see if that works. You might reset your router. You might reboot your computer. You might delete the .plist files. At some level of frustration you might even decide to nuke and pave your iMac.
With some experience, this kind of random approach can produce results.
At least, it can appear to produce results, and, indeed, the result may even work for a while. Or forever.
But a random approach to fixing problems can also lead you down a frustrating path of endless hours of trial and error that sees you tearing your hair out and leaves you no closer to a fixed computer.
In extreme cases, random trial and error can make the problem far worse and turn what might have been a simple fix into a full system rebuild.
To continue using our example above, it might turn out that there was nothing wrong with your computer at all. Instead, your Internet link had an outage. But by the time the outage had fixed itself you’d damaged your computer and couldn’t tell that the problem had already fixed itself.
This is where a systematic approach to diagnosing the fault can really help.
At this point, it’s worth talking about the difference between a fault and a symptom.
In general, whenever we’ve got a computer problem. The stuff we observe about that problem are symptoms. A symptom is an indication of what might be the root cause of the fault. It’s fairly rare that the symptom is also the problem. Most of the time, it’s an indicator of where to start looking for the actual cause of the problem.
All too often, a good diagnosis is hindered by this confusion.
Especially when you’ve actually got multiple symptoms there to help you if you only look for them.
Identify Potential Problems

A really good starting point is to consider where the fault might be. In our “can’t web surf” example, this might include:
- Safari isn’t working properly
- Other software on your computer is interfering with your web browsing
- Networking software in the operating system is corrupted or mis-configured
- Network connection out of computer isn’t working
- Other network equipment on your network isn’t working (e.g. router, switch, etc)
- Cables are unplugged
- Internet connection is too busy to load web pages
- Internet connection is down
- Phone line is disconnected
- Web site(s) you’re trying to load is/are down
There’s ten quick areas that might be relevant to the fault.
What you’re trying to do is give some thought to the things that might result in your problem. By doing this, you’re already starting to think about the actual problem rather than the symptom. As you think about these things, you’ll probably start to notice other symptoms that may not, at first, have appeared relevant.
Identify More Symptoms

There’s almost always more symptoms.
Let’s say that in this case, you might also notice that you can’t get any email either.
Unless you’re using Safari to read email online, you can immediately eliminate the possibility that Safari isn’t working. If that’s all the problem was, you’d still be able to get email.
The more symptoms you can identify, the easier your diagnostic process becomes.
A good way to identify more symptoms is to think about your list of possible problems and see if you can come up with symptoms you might observe. For example, you might have gone to make a phone call and noticed a really bad static noise. This would then be a symptom you could add to your list.
Let’s go ahead and add a few more symptoms for our example…
- You can still access the movies you’ve got stored on your NAS device
- The MacBook Pro you’ve got connected via Wi-Fi won’t load web pages or pick up email either
With this information, we can go ahead and rule out software on your computer. If that was the problem, the MacBook Pro would be working fine.
Because both computer can access your NAS device, it’s unlikely that there’s any real problems on your local network. That means the equipment that runs your own local network is probably working fine.
Finally, because email isn’t working either it’s probably not an issue with the web site(s) you’re trying to reach.
At this point, your problem list comes down to:
- Internet connection is too busy to load web pages
- Router isn’t working (network equipment not working)
- Internet connection is down
- Phone line is disconnected
With just a few extra nuggets of information our list of ten areas to work through is down to four.
Wow! That was pretty easy.
Test for Problems

It’s not enough to pick some tests at random and see if the problem goes away. Before you even start the test it’s worth thinking about what that test will tell you.
In our example, you might try power cycling your router.
Why? What will doing this tell you? What problems would this fix?
Your router is the gateway to the outside (Internet) world. It might suffer a glitch of some sort that has an effect similar to a two year old putting their fingers in their ears and chanting “nah nah nah” over and over again. If you power cycle your router, it might fix this.
That’s a good start to understanding. But what if it doesn’t fix it? What does that tell you?
More importantly, does it tell you that the router is faulty?
Unfortunately, no. It doesn’t.
That’s because this test would also fail if your Internet connection is down from the ISP end or if your phone line has been disconnected.
This is the important nugget of understanding right here.
Your test isn’t all-inclusive.
It’s going to tell you something about the nature of the problem, certainly. But not everything about the problem.
A really good test is one that can tell you everything you need to know about the problem in order to find a fix.
A bad test will tell you almost nothing about the problem.
Let’s say that you decide to reboot your iMac as one of your tests. What does that tell you about this problem?
In reality, almost nothing. It would be a fairly bad test to use to determine what’s going on based on the information you’ve already got.
It’s not always possible to find just one really good test. You may need to do a few tests before you can really lock down the source of a problem. But, I’d also suggest that in the vast majority of cases, if you’re running more than half a dozen tests you either haven’t identified all the symptoms available to you yet, or you haven’t really found good tests.
Why?
Because truly complicated problems in more than one area aren’t all that common. When you eliminate a local network problem because two computers on the network can access each other but not the Internet you’re going with an assumption that two computers haven’t suddenly become faulty at the same time. That’s usually a pretty good assumption because it doesn’t happen very often. If another symptom was that there’d just been a thunderstorm and now your fridge doesn’t work then, unfortunately, it’s not an assumption you can make.
This is why looking for symptoms is so important. It helps you to frame your tests to get to a result.
Conclusions Follow Results Not Assumptions
At this point, the potential problem areas list has been cut down to:
- Router isn’t working (network equipment not working)
- Internet connection is down
Why can’t you eliminate the router as a problem? Most modern routers perform two or more different functions that can be somewhat independent of each other. They act as a network switch, a wireless access point, and a gateway between your local network and the Internet. It’s possible for some of these functions to still work while other parts have failed completely.
At this point, you still don’t have enough results to allow you to know for sure what problem you’ve got.
If you have another router (that isn’t normally in use, but that you know is working) you could try connecting that instead of your normal router. If you still have a problem, the Internet connection is down. If not, it’s a faulty router.
Throughout this article, I’ve used one particular problem as an example.
The EXACT same process applies to EVERY computer problem.
Identify possible causes. Look for more symptoms. Work out some tests that help you lock down a cause. Base your conclusion on results and not assumptions.
It looks easy when it’s written down like this. Unfortunately, it isn’t really quite that easy. Being good at it requires a level of understanding of technology - otherwise you don’t notice important symptoms. The good news is that it’s a skill that you can develop, and the more you come to understand about the technology you use, the better you’ll get at applying the process to any problem you encounter.
Now here’s the good bit for everyone, no matter how much you know about technology. If you’re aware of the process, you can be on the lookout for stuff that’s going to matter to a tech who has to fix your computer for you. You can let them know what you’ve observed. This helps them cut through to the problem faster and more reliably which will often mean a less expensive repair for you.
All really good computer technicians have learned how to apply this process (even if they aren’t conscious of having learned it). In fact, you could probably argue that it’s the defining characteristic of a good computer tech.
Don’t believe me? Apple’s ACMT training materials discuss this process and the potential pitfalls of not using it.
Photo Credits:
MacBook Pro Innards by flickr user Lars Plougmann
Problems by flickr user D’Arcy Norman
Rusty Components by flickr user tismy_photostream
MacBook Down by flickr user Buffawhat
David Freeman is an Apple Certified Macintosh Technician and the proprietor of Outback Queensland Internet (aka Leading Edge Computers Longreach). He has worked as a technician since 1995 and been involved in computers and the Internet since 1988 when he purchased his first computer (an Amiga 1000).
vBulletin Message