I found this information last year on how to get an Amiga 500 Chinon FB-354 floppy drive with a functioning disk activity LED working in my Amiga 1000 and produced this set of instructions on how to do it. Although I have posted it elsewhere I thought folks here might find it helpful too (do this at your own risk).
Steps to follow...
1) Solder a 2200 ohm (2K2) surface mounted (SMD) resistor to the Chinon FB-354 floppy drive motherboard at location R13 to enable power for the disk activity LED locations A & K on the front of the motherboard.
2) Solder an LED to locations A & K being careful to attach the LED anode to location A and the cathode to location K.
I have uploaded a diagram (JPEG) with this post showing the relevant locations.
Credits for original mod information.
Jan Beta's YouTube video...
"Amiga Internal Disk Drive in External A1010 Case".
(The video contains Chinon FB-354 LED activity resistor mod info at 10 Minutes 40 Seconds in).
[ Show youtube player ]
Jan refers to the mod information originating from...
Stephan Ricken at the brotkastenblog.
https://brotkasten.blog