A500 external and internal floppy conflict

[Dr Laser]

Hey ALL

I'm having a strange issue with my Amiga 500. When I boot with both floppies attached booting goes to first screen both drives go insynch and start reading together like they are both fd0. Of cuz this cuz a error message appears. I took external floppy part. It's the same fb-354 but with different control board. When I disconnect external floppy drive my 500 boots up no problem. HELP!

Thanks.

[Dr Laser]

Thanks a lot guys. I swapped 8520 chips....and it works. I'm formating floppy right now. Will need to get replacement chip. Thanks again!!:)