Advice needed: Wait or send to depot?

[famman]

My T410s is connected to an external monitor via display port. Fn + F3 turns off my screen as per normal, but hitting any key doesn't turn the screens back on. Instead, all I can see is the mouse pointer, which is flashing. Occasionally, if I hit Fn + F3 again a few times and play with the mouse the screens will come back on, but usually I have to put the computer to sleep and wake it for the screens to come back on. Works fine when not connected to an external monitor. Diagnostics gave a message for the NVIDIA card saying that Primary Surface Test = Abnormal Exit, but didn't fail. After updating bios and PM driver, Lenovo support concludes that it's a bad board and advised to send it in (computer is just over two months old). But, my past experience has led me to avoid service if possible (nice to have warranty if major problem but service can also create new problems).

What are your thoughts on this? Anyone else have this problem? Any ideas what is the problem? Would you suggest just to leave it and see if it eventually gets resolved with an NVIDIA driver update? Or does it sound like it definitely needs a new board?

[famman]

Can anyone with a T410s with switchable graphics please confirm that the Fn + F3 setting resumes as it should when using the NVIDIA/High Performance setting with an external monitor connected?