Xpantastic!

Hi,

You could try and change the position of the CEM3374 chips one by one 
to see, if and whichof the the chips is broken. If the non-working 
voice is despite changing the chips always in the same position, then 
something else must be broken.

Before anything do a factory reset and run all the other tests. I think 
there are some more in the Service Manual.

Good luck!
Tiitu