[Coco] Floppy drive problem need help

[Warren Hoslet]

>I am having a problem with a floppy drive I purchased from Cloud-9 a while
>ago. It is an ALPS Electric Co.
>Model DFC222B02A. I purchased it as new old stock.
>
>The problem is that when using a Tandy FD-502 disk controller the Alps 
>drive
>will not DSKINI under RSDOS
>or boot Nitros9, when it is used with another drive on the system. When it
>is used by itself it works fine.
>
>Normally this Alps drive is my drive 0 and I have an IBM XT drive (YD-580)
>as drive 1. With a Disto SCII
>these drives work fine together. When I use a FD-502 the Alps will not work
>as described above.
>
>I have tried different Coco 3s, different ribbon cables, I even moved the
>Alps drive to drive 1 and it acted the
>same. Still the same problems. I have a Panasonic 360K drive. I tried it
>with the Alps drive and had the
>same problems. When I removed the Alps drive and used the Panasonic and the
>IBM XT drive together everything
>works fine.
>
>So to be exact, I can't use this drive in a two drive system. With all the
>swapping and testing I am able to do it can
>be nothing other than the drive. What gets me is why it works with another
>drive using a Disto SCII and I only have these
>problems with a FD-502 controller.
>
>The Panasonic drive belongs in my Win98 PC I use to make CoCo disks, so 
>this
>will leave my coco with a single drive.
>Does anyone have ideas about what the problem is or should I start looking
>for another IBM XT YD-580 and forget about
>this Alps drive?
>
>Thanks!
>
>-Charlie
>
-
Sounds like it may be a termination problem. Only one drive in the chain 
should have terminating resistors, and it should be the drive located last 
on the cable (furthest from the controller). Sometimes you can have multiple 
drives with termination and everything works fine, other times it won't.

You can usually remove termination from a drive by either changing a jumper, 
or removing a component. The component style is usually a colored (blue for 
instance) DIP or SIP in a socket. Most 3.5 inch drives don't have removable 
termination, so if you have one of those, you should keep it in the last 
slot on the cable and remove termination from your other drive.

Good luck!