PC40 III floppy drive question

[richo132]

Hi all,
I've just acquired a PC40 III aka Commodore 286-12.
After taking a Dremel to the RTC and attaching an external battery, I can now boot the PC to the IBM DOS installed on the 42Gb HDD. So far so good, however I can't get the floppy to work.
The PC is fitted with a 3.5" Chinon FB-357 Rev C.
It is mounted in a metal Chinon drawer (Chinon FB-3571) that adapts to a 5.25" bay
There is an adaptor card with a socket to plug onto the back of the drive and an edge connector for the ribbon cable.
Must say I've never seen one of these before.  The drive is found during the POST, and apparently passes whatever tests are applied.
However, all attempts to then read data from the drive fail
I'd be happy to receive any advice on this.
What is the correct drive for the PC and what jumper settings are needed on the drive, the adaptor board and the motherboard ?
Thanks in advance.

[richo132]

Thanks for all comments.
I've come across a couple of other posts that seem to confirm the FB-357 is a low density drive ie capable of 880Kb in an Amiga or 720Kb in an IBM.  
Also the IDE cable in the PC40 does not have a twist for the last drive. Therefore the FB-357 either needs to be the first drive ie closest to M/B or have the DS jumper set to DS1
So, I have a few new things to try:
1. Test with a 720Kb floppy
2. Try an IDE cable with a twist
3. Check/reset the DS jumper
4. Replace FB-357 with a 1.44Mb FDD
5. Try the FB-357 in an A500
NB the BIOS has a selectable option for 1.44Mb,
so I presume the PC will support it.
I'll post the results of further trials.
Cheers.