Instructor: In this lesson, we're going to talk
about step three of the troubleshooting methodology
which is test the theory.
Now, CompTIA writes this down
as test the theory to determine the cause.
Once that theory is confirmed,
determine the next steps to resolve the problem.
If the theory is not confirmed,
reestablish a new theory or escalate
and this is what we're focused on in step three.
So, in step one, we identified our problem.
In step two, we came up with an idea of what
we thought the probable cause of that problem was.
And now here in step three,
we are going to test our theory to see if we were right.
Now, up to this point, we have done
a lot of work in thinking about the problem
but we haven't done any kind of configurations
or changes to the system to try to solve that problem.
And now that we're here in step three,
we can finally do that.
So, let's say for example
we had a system that wouldn't turn on,
well, if we have a system that won't turn on,
it can be lots of different problems,
but we thought the problem was this computer
wasn't plugged into the wall outlet.
Now, that's a really simple theory to test.
We can simply trace the cable from the back
of the tower into the wall outlet and see
if it's plugged in and if it's not,
that tells me that was the problem.
Let's plug it in, turn on the computer
and see if it boots up.
If it does, that was the problem.
We have now confirmed it
and our theory has solved the problem.
But let's say we got there
and the cable wasn't plugged into the wall,
we plugged the cable into the wall,
we the power button, and nothing happens.
The computer still won't turn on.
Well, now our theory of it being unplugged
being the root cause is no longer valid.
So, we need to now create a new theory
based on the different symptoms we had,
based on what we've observed
and based on what we've done so far,
we know that what we thought
was the problem is no longer the problem.
And so we need to figure out what is the next theory
or probable cause that we're going to attempt.
In this case, I might say the wall outlet
doesn't provide enough power,
so I make a theory that the wall outlet is the problem.
So, I step back to step two, I create a new theory
and I say I think the wall outlet is the problem.
Now, I'm back in step three.
I need to test that theory.
So, I grab my volt meter, I plug it into the wall,
and I test and I see that I'm getting 120 volts AC.
And since I'm located here in the United States,
that's perfectly fine.
So, that's not my problem.
So, I need to establish another theory and try again.
So, maybe I think it's the power supply itself
that's the problem.
And now I can use that as my new theory
and start working towards that to confirm it.
The idea here is we guess on something,
we then try to test that theory,
and if we test that theory and find it's not the cause,
we are then going to have to get a new theory.
If we did test the theory and we confirm that theory,
the next steps are going to be
to resolve the problem for the long term.
So, at this point, if we tested the power supply
and found that it was faulty,
we would have now confirmed our theory
and at this point, we would then need to determine
the next steps that we have to resolve this problem.
That could be fixing the power supply,
replacing the power supply,
or maybe even replacing the entire computer
depending on how old that unit is
and what your corporate policies are.
Another thing to keep in mind here in step three,
when you're testing the theory to determine the cause is
that you really have four possible outcomes.
The first is that your theory is confirmed
and in this case, you're going to take steps to fix it.
The second is your theory is not confirmed
and you need to come up with a new theory
and then try to test that theory.
And if you find it, then you're going to fix it.
The third is you identified the problem,
you've tested your theory and you figured out
what the problem is, but you don't have the skills
or the authority to fix that thing.
For example, maybe you've identified
that this particular fix is going to require a $10,000 part
and you're not authorized to replace
that part in that system.
Well, in this case, you'd have to escalate
that up to the team that's responsible
for that server or that piece of equipment,
so they can then replace that part
or they get the approval to replace that part.
Another side of this might be you don't
have the skills to fix that thing yet.
Maybe you found there was an issue that was happening
across multiple systems that you're supporting.
And when you look at it, you figured out
that the issue had to do with a group policy
that was being pushed out from the Windows server
but you don't work in the Windows server group.
So, you're going to have to escalate this issue
over to the Windows server group so
that that team can change the policies
and configurations that they're pushing out
to all the systems across the domain
and fix this larger problem.
Another issue might be where you have to escalate this
and bring in some outside support.
Maybe you found out that the reason
this system isn't working right is
that it was infected by malware or there's an attacker
in your system and they have control of that system.
In that case, as a technician,
we are probably not going to be the ones to fix that,
but instead we're going to call
in the cyber security experts who are
going to come in and kick those bad folks out
of our network and off of that box
so that we can gain access to it once more.
Again, a lot of this is going to depend on your organization,
the policies, procedures, and authorities
that they give to the technicians at different levels.
But keep in mind that one of the things
you could do is escalate this when there's an issue.
Now, the fourth possible outcome is
that you tested your theory, you come up
with a bunch of theories, and you're just stuck.
You don't know what the right answer is.
You don't know how to fix this problem.
And in those cases, you would again need
to escalate this to the next higher level.
In most organizations, we have a tiered support structure
of tier one, tier two, and tier three support technicians.
Tier one is going to solve all of the most basic problems.
Over time, you're going to gain more skills
and you'll move up to tier two
where you can solve some more advanced problems.
And when you get to tier three,
that's really where you start dealing
with the subject matter experts,
people who are the system administrators,
the server administrators, the cryptographic
and cybersecurity experts, and things like that.
Now, over time, you may move into those positions,
but today when you're first starting out,
you're probably going to be in tier one or maybe tier two.
And so there are going to be some things that you
just don't know how to identify or how to fix.
And in those cases, you're going to
want to escalate those tickets up to tier two
or tier three for additional assistance
so they can solve the problem for the young user.