I had a day ago the same thing u did. A day ago i tried the swap trick mod. All are working fine... The next day i made some swaps... Suddenly the drive stopped to take in disks. The blue led lights up indicating that a disk i going to be put in, but the motor doesn't work. If you manually insert the disk using the external power to function the motor the disk gets in normally but it will not spin.
I rebuilded and checked the drive several times but it doesn't work again. Gazza85 has had the same prb, and here the facts:
-Because of the external power (i used only 1.5V) something has happens to the the main circuit board under the drive (see attached files, taken from Gazza85 thread)
-I don't think that the prb occurs after 3-4 swaps but if you overdrive the motor
-The prb happens as far, only on JAP-made consoles
-Happens on FW 1.60 and up so far
-Happens only if ps3 is running?!
And the NICE:
PS3 works with and without the BRD. No bios check. neither an error.
Can't play RFOM not watch DVD's
No where to find a replacement (notice that are replacement of the Blu-ray lens)