[Coco] Can't copy real floppy to CoCo-SDC on a CoCo 2

[Al Hartman]

No Robert...

1. In order for drives to work on a Coco, or other TRS-80 - every select 
position must be jumpered, pin 32 must be cut and jumpered to pin 6. Then, 
the missing pins at each connector determine the drive select. But, you are 
right that drive 0 MUST be terminated and at the end of the cable.

2. On the PC, IBM made life easier for it's techs by having each drive 
jumpered to DS1, and the cable twist sending the drive select signal to the 
correct pin. I've read both that you have to remove termination on all 
drives except the last one, or that the termination is a lower resistor 
value so you can just ignore it on all drives as the cable is short, and 
there's no much ringing on that short a cable anyway.

I know that in servicing and building systems from the early 5150 PC days 
until today, I never had to worry about termination.

-[ Al ]-

-----Original Message----- 
From: Robert Gault

mike at borncoco.com wrote:
> I removed the SDC and MPI and I'm having issues with accessing floppy 
> drive 1. I may have some wonky jumper settings on one of these floppy 
> drives. These are not RS drives & not identical. I'm not sure why that 
> would cause things to behave this way, but this certainly needs to be 
> addressed before I troubleshoot any further.
>
> Cheers,
> -Mike
>

Coco drives are addressed by the cable not be jumpers in the drive. If you 
have
such jumpers, they probably should be set to 0.
There should be only one terminator resistor block in your system. If more 
than
one drive has such, the last (highest number drive) should have the 
resistors.

PC drives may not be able to be used as drive0 without a twist in the cable.
Such a drive probably will work as drive1 without changes to the cable.

Robert