I was in a similar situation, but my power supply just burned out and the partition on the disk was damaged. I used RAID Recovery to recover the data.
NAS Fried
I recently did the latest firmware update for my QNAP TS-253B NAS. Within 5 minutes of restarting after completion of the update, smoke started billowing out of the back of the NAS. The NAS is now dead in the water. Is it worth paying to get it fixed, as it is out of warranty? Thanks in advance.