Floppy drives not wotking.
OK, so mid 90's I was doing onsite repair for homes and business' for a big computer retailer in Dublin.
I had a call to go and replace a floppy drive. Went out and tested the drive, it worked, but the customer said it was intermittent, so I replaced the drive anyway, tested it, it worked fine. Took the replaced unit back to store, plugged it in to a test machine and it worked fine, so boxed it, labeled it as used working and sent it back to the parts dept.
A week later I got a call (different customer) with the same problem. Went out with another replacement drive and again the customer said it was intermittent. Tested the drive and it indeed didn't work but it wasn't that the drive didn't work it was that the BIOS on boot didn't detect the drive.
So, replaced the drive unit and it wouldn't see the new drive. MB failure then maybe? Had one of those for the same machine out in the car, so brought that in and started unplugging everything to disassemble and had a brief idea to test again with nothing but the monitor, keyboard and mouse attached.
Drive worked fine. WTF?
Plugged the printer and scanner back in. Rebooted, drive didn't get detected by the BIOS.
Now I start thinking about the other customer. What make and model was his machine? Pulled out my Nokia and phoned Customer Care line to get the details of the other customers machine. At this point the current customer walks in to the room and freaks the fuck out and runs out of the house. Another WTF moment. Got the details and find that both customers have the same all in package of computer, printer and scanner.
OK now, for some reason, I decided to power up the scanner before booting the PC.. lo and behold, drive works, reboot with scanner powered off (but still connected), drive doesn't work. Suddenly it all becomes clear.
If this particular machine has its packaged scanner connected but not powered up on boot the BIOS would not find the FDD.
Found the customer outside the house and explained the problem and to just keep the scanner on when booting while we worked on a better fix (how this wasn't found in testing the package before it went to market I don't know).
He apologised for running out of the house when he seen me on the phone and explained that he had a phobia of phones which also explained why I couldn't contact him that morning to let him know when I'd be arriving. That was another WTF?