I did some research on what it may be that kills so many modded floppies and stumbled across 2 things: If the LED you use heavily differs from the original one it may lead to malfunctions/damage - mainly if the new one is weaker - because it lets too much current flow back into the Floppy which can do damage. a lot of people use magnetic screwdrivers - you can quite easily destroy the floppy's read/write head with these things so you should measure the original led's voltage and mA's and replace it with a similar one and take care about magnetism... hope that helps
