I understand the confusion. In this case there are two reasons why you would use the definite article the:
- You are talking about a named product or component. While there are many of that component, we can group them all into a kind of "generic" instance. For example:
Hi, Apple support person? I have a question about the iPhone.
There are many iPhones, and if you wanted to report a problem with one of them as separate from all the others, you might say "an" iPhone. But in your case it sounds more like you are talking about all similar components.
- You are talking to someone who you can assume knows what you mean, so you don't have to add context to specify which product or component you mean:
Hi, good friend! Let's all go down to the village pub later and have a pint!
Yes, there are many pubs in the village, but I can assume my friend knows the one I mean. In the same way a support person will know that the item you are talking about is something they make -- because otherwise why would you call them?
On the other hand, if I am talking about one component of many which is failing, or I don't know the name of it, I can use the indefinite article instead:
Hi support person! I opened up my computer and there's a green board-like thing in there. It's just blinking at me and my computer won't turn on.