I couldn't find one when mine went iffy, so I made one... Got some dirty great power resistors from farnells IIRC the ones I got were 10Ohm 80W @ £16 each completely over engineered it and its works great :-D
http://uk.farnell.com/jsp/search/bro...D2031%2B215516
Correction: 10 Ohm seems really high, it may have been these 0.6 Ohm / 0.7 Ohm I used....
http://uk.farnell.com/welwyn/wh100-r...r68/dp/1768197