No on both accounts.
Unless thats a higher end HU its not worth the bother.
The amp, unless its a higher end unit isnt worth it either.
Since I have an amp with an issue Im familar with repair centers right now.
I guess this guys really good and thorough, but isnt the cheapest:
http://www.db-r.com/
This guy is cheaper but not as thorough:
http://amprepaircenter.com/
And this guy is someone I found on the forum that does it on the side as a hobby. Seems like an alright guy, might be worth a shot:
stretchjr20061974@yahoo.com
His name is Robert.