Good evening and thanks for letting me join the group.
I have an Apple IIe that I'm in the process of restoring. It came with three disk drives, two 5.25" and one 3.5" Unidrive, but no disks of any kind. Out of curiosity, I attached the 3.5" drive and started the computer. I was greeted with "static" on my monochrome monitor and after a moment, I saw a small curl of smoke coming out of the computer. After shutting it down and cracking open the case, I saw that the ribbon cable from 5.25" controller card was scorched. It wasn't evident from the outside that there were separate 3.5" and 5.25" ports. After seeing this I connected the correct drives to the correct controllers and everything seems OK. The computer then started up the the "apple II/e" screen. Did I ruin anything?
Actually, I don't know. I could look at the pinouts and probobly tell. If the cable is scorched bad, you may want to get a new 5.25" controller card.
I know that if you plug the UniDisk into a Laser Universal Drive Controller bad things happen and you blow the controller and the drive.
Perhaps someone else may have a better answer.
Unfortunately you may have damaged either the computer or the drive. The UniDisk (not "unidrive") only works with the Apple IIc or with a special card called Liron.
Try not to use that 3.5 drive look for photos online, it should be whiter than the other drives. The right drive is platinum color and has a "dot" in the eject button.
Maybe somebody can check that drive for you later.
If you don't have any disks for your IIe then it's harder to tell. When you turned on the power, did the 5.25" drive keep running?