A friend of mine has the same issue. This is what he did:
QUOTE
Got my Wii to work the game cube power pack works with it you just need to cut the plastic a bit on the end of the plug so you can match up the + and - correct and it works great
And I agree, Nintendo has changed the way game will be played. So far, clocked in over 7 hours of gaming (mostly in Wii Sports)
QUOTE(LoXodonte @ Nov 20 2006, 04:02 PM)

thx for the response, is their a link you can point me to from that quote so I can read everything he did?
heh, I'd just hate to break this even more ya know...you'd think that under powering something might have some long term affects.
He did it himself. Everything in the quote is all i know without seeing it. I'm guessing he took and gently broke off the plastic around the end of the GC power adapter so that the positive and negative terminals would match up.
QUOTE(LoXodonte @ Nov 21 2006, 12:42 AM)

thx, working great

I made a miiiI!!!!!!!!
Glad to hear it. I still suggest replacing your original through Nintendo though. Got any pics to show us?