Thanks for the feedback so far, guys - I really appreciate it!
Once the 9.6v NiMh mini battery comes in, I'll let everyone know if it has solved the problem or not and I can put this thread to rest as a note to anyone buying a new CA90. If worse comes to worst, hopefully all I'll have to do is swap out the spring. Let's hope it's nothing more complicated than that! Otherwise, woooo, bye-bye money...
In the meantime, suggestions and possible solutions I may have overlooked are still welcome!