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.

[Kronos]

42GB in a PC40 ? Now that sounds like a good idea


Bout the floppy, check the power-connector and if that fails replace
with a bog-standard 1.44MB-floppy.

[adolescent]

5.25" floppy drives used edge connectors instead of IDC.  What you have is an adapter to use a 3.5" drive on 5.25" type cable.  Not so uncommon back in the 80s.  

BTW, the computer might not support HD floppies.  Try covering the hole or using a DD floppy to see.

[Protek]

Isn't the HD floppy drive a standard in AT form factor?

But as adolescent said, the card edge connector adapters were common in the good old days. You could just try to change the ribbon cable to a modern one and omit the adapter.

[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.

[Zac67]

IDE != floppy cable !!

IDE (hard disc) is 40 pin, no twist, one contact may be punched through between end and middle plug.

Floppy (Shugart) is 34 pin, usually with a twist been end and middle plug.

[uridium]

G'day Richo,

I'm in much the same boat. Did you end up finding out how to get it to boot? Mine refuses to boot with a 720Kb or 1.44Mb MessyDOS diskette up it. I've also dremmeled the clock chip and strapped a battery to the dallas chip so I can now save date/times etc and config. Any ideas? It complains even in the original config that the floppy 0 is misconfigured, irrespective of it being set as a 720kb or 1.44mb in the CMOS.

Ideas?

Best Wishes,
Al.

[rrete]

Hi Uridium!

Same post at commodore128.org. The same problem for all, in my PC35 III I've tried w/twist cable wo/twist cable , as DS0 / DS1 at the end of the cable, at begining too, w/adapter and wo it always with a Chinon FB-354 and a Epson 5 1/4 units and.....noooothing. There is a site where can be seen the default floppies of C= PCs and others so 354/357 must be work. My FB-354 is a HD unit.

see here: http://www.amiga-stuff.com/hardware/diskdrives.html

In other point, bios can handle up to 202 Mb hard disk, in mine is the biggest.

Nobody knows the answer to this problem?

[shaf]

The Chinon FB-354I Has a set of 8 Jumper Blocks labelled 1 to 8. It is a 720K Drive
The Default settings for AT (286 PC-40) are:
#7 = ON (Disk Change on Pin 34)
#6 = ON (Motor ON by Motor ON Signal)
#2 = ON (Drive Select 1) Sets As Drive B

If only using A Single Floppy Drive than Unplug Jumper #2 and Place it in the Jumper #1 position to set Drive Select 0 (Drive A)

Jumper 7 might have been cut because the adapter was used in an XT System in which case you will need to re-connect jumper 7.

[rrete]

Hi
Mine sure is a HD floppy, maybe wrong labeled, I'ts was a spare for my A4K if the actually broke (I hope no). I've been using for a time in the A4k and working fine with 1.76 Mb disks, checked: it has switch for "HD" disks marked on the PBC too.
It has only one rear jumper to change to DS0 or DS1, the jumpers you say no. Maybe I must open it to see it?

[shaf]

There are multiple versions of the Chinon Drive all slightly different, I believe rrpete's version is the FZ-354IS which has no Jumper Block on the 5.25 cable adapter.
There are also Jumpers on the FZ-354 Drive itself and are set at Factory default to DS0, MM, DC, & TTL.

[rrete]

Mine is only labeled FB-354 no more. I'm not now at home but I'll look for in the pbc  more specifications or I'll post a photo better.
Thanks