Hi,
I also made the test to chain a A1010 and a A1011 Commodore drive on my A1200 and I have the same result as you :
- A1010 is working well on the external connector when it is alone,
- A1011 is working well on the external connector when it is alone,
- when the A1011 is linked to the A1010, A1010 is working but A1011 is not working.
Indeed, it seems that when linked, the A1011 is not powered through the A1010 (I cannot hear the typical "clic" inside).
I have a A1200 with a 200MB 2.5" hard drive + a GVP A1230 Turbo accelerator card which probably need a big amount of power. My power supply is the standard A1200 power supply. As you said maybe this power supply is not enough powerfull to power the second floppy drive.
I will try to get the powerfull A500 power supply in the future and see if the problem is solved with this change.
Maybe even if the power supply is more powerfull, it will not solve the problem if the problem is linked to the fact that the external floppy connector is limited to a certain amount of power which is under the need of a A1010 + A1011 floppy drives.
I also heard several times that 1 external floppy drive is only supported (even it is said 2 or 4 in some documentations) but I do not manage to find the truth on the net.
Sébastien