External dvd drive repair or replace?

My DVD player is an external Pacific-Digital dvd burner 4x max cd 2 times max dvd. The last error it gave me was a tracking servo error.
I try to burn DVDs and most of the time it does not even recognize I have a blank dvd in the drive ready to burn. It will tell me please insert a blank dvd, which is exactly what that is in the drive.

I just bought Maxwell DVD-R disk a pack of 25 not one single dvd does my drive recognize! the Sony DVD-R's I have at least once in while it will recognize, but truthfully I have made way more coasters than I have successfully burned.

So there seems something up with my dvd burner that does not affect my cd burner which is the same burner. Maybe because the dvd burner must be more accurate? also I am using a usb 1.0 port my computer is before 2.0

I figure I would like to fix it or replace it the cheapest way, money is short. I thought if I have to replace it, if I could just replace the drive itself maybe with an internal drive in the external case and not the full external dvd burner if that could be possible.

Thanks,