For IRiver repairs,
www.cherryfusion.com "claims" to do H10 repairs. I have never used them so can't give any information. Perhaps someone on the forum has some experience with them. Their web site was working last week but is not today. I don't know if it is a tempoary problem or the company has gone away.
The only other option I know of is to try to get a bad one on ebay and hope you can make one good one out of two bad one's. I am going that route with the one I have.
It would be nice if someone could come up with a schematic of the 20gb version. It would take a lot of guess work out of trying to fix one.