[Coco] STATUS - Re: Resurrecting a CoCo (26-3001) with a 26-3029 FDC.

[Gene Heskett]

On Friday 12 September 2008, J.P. Samson wrote:
>On Sep 12, 2008, at 8:12 PM, Ryan Pritchard wrote:
>> I mean that the cable is on correct, the drive light and motor turn
>> on after I press ENTER when entering DSKINI0 to format the
>> diskette.  The drive proceeds to spin the disk and move the head for
>> about 35 track adjustments then makes a normal type of I am not
>> going to complete my job grind noise, and then I get the ?IO ERROR
>> message.
>
>How many different drive cables have you tried?
>
>Unfortunately, the best way to track down which component is the
>problem is to have multiples of everything (e.g. disk controllers,
>drive cables, floppy drives, CoCo's).
>
One thing that no one has mentioned yet, the cable terminations.  Floppy 
drives are a bit like scsi in that the cables are loaded at the far end, and 
it may be possible that if the drive isn't 'terminated' correctly. there 
could be data errors.  This 'termination' should only be installed in the 
drive on the far end of the cable, and should be removed from drives 
connected in the middle of the cable.

Continuing on down the menu:

Severely dirty heads could also do that since the formatting of a floppy is 
driven entirely by the stepper and the index pulse, and if when it steps back 
to track zero to begin verifying the format, and can't find a valid first 
sector of the first track, it will sit and re-seek several times before 
giving up, throwing up the IO Error when it does.

On single sided drives, the felt pad that replaces the 2nd head may have come 
off, which would give a very poor and intermittent contact with the disk, and 
again the ?IO ERROR is returned. A small flashlight through the disk slot 
near one end so as to see past the spindle might be an 'illuminating' 
experience. :)

>-- JP
>
>
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-- 
Cheers, Gene
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It'll be a nice world if they ever get it finished.