Thanks to everyone for the replies.
I went to the apple web site to see if the drive was supported, It was.
Drive arrived by USPS very quickly considering I live in the boonies. Only $49 plus minimal shipping costs.
Replacing the drive in the QPS case was quick and easy.
Hooked it up, and turned it on. (No smoke thank goodness.)
Started Toast, drive recognised. All speeds recoginsed by Toast. Burned at 52x on a TDK 24x certified disk (only kind I had) worked great.
Thanks again everyone.
Jochen