Wouldn't make any sense; the postage two ways, the risk of getting it wrong... the time to do the work, the time to test, the time to go to the post office to send it back. How could one turn a profit and offer a warrantee period?
Even worse, someone who has given it a try and then sends the mess.
Just not worth the hassle, and before anyone asks, I'm really not interested; just buy a new unit, it would be cheaper.
Anyhow, who am I to deny you the joy of having repaired something yourself?