Re: Disk ][ Drives not working

[Don Bruder <dakidd@sonic.net>]

In article <pan.2004.06.30.23.17.16.824452@alirossdotco.uk>,
 Alistair J Ross <mailat@alirossdotco.uk> wrote:

> Hello again,
> 
>     Thank you to all of you lovely people who offered to send me a disk with
>     DOS 3.3 in my recent problem of chicken-and-egg: getting DOS to my Apple
>     ][ Europlus.
> 
>     Well. I have now recieved said copies of software (thank you very *VERY*
>     much), so I went about booting the disks (I have two copies of the DOS
>     master disk, just in case). Unfortunately, the ][ just sits there on
>     startup with APPLE ][ on screen. Drive 1 moves the head back to the rear 
>     of
>     the drive (if not already there) and it tries to move it's self back even
>     further (is this called calibrating?!) - in doing so, the drive gives out 
>     a
>     (what I would call) slightly irregular thud, thud, thud sound. About 10 
>     or
>     so of these thuds and the drive head ceases to move against it's stopper.
>     The drive motor continues to run however, until I hit RESET.
> 
>     Both of my drives perform the same issue when they are set to be Drive 1. 
>     I
>     have 2 Drive ][ controller cards which both do the same thing. I have
>     stripped the drive of it's casing to see exactly what is happening but
>     everything (with exception of the heads simply moving back to the rear of
>     the drive and hitting against the stopper repeatedly) is normal. There 
>     are
>     no immediate signs of wear and I have ran a non-abrasive head cleaner
>     through the drive just in case. 
> 
>     If I manually push the heads to the front of the drive, then the drive
>     first of all pushes the heads to the back again, before resuming the 
>     normal
>     thudding, so it seems to know that its got to go back to the bottom to 
>     seek
>     for something. 
> 
>     Anyone any ideas as to why this is happening? Should I shell out the 20 
>     or
>     so pounds on Ebay to buy a couple of new drives? I don't really think 
>     there
>     is that much wrong with these drives. Do you?
> 
> As always, many thanks in advance.
> 
>     Alistair Ross


You're describing a drive that's not seeing any startup code on the 
disk. The next thing to wonder is "Is this because the drive is damaged, 
or because the disk doesn't have any boot code?"

It's possible that the disk was written, or the drive is, out of 
alignment. Although the recalibrate - the "thud thud thud" you describe 
- should get it lined up over track 0. That may not get the head to 
where the data is if the drive that wrote the disk wasn't in good shape.

Let's try this:
Power off the system. Drop a disk into the drive, and power it back up 
up. Wait until the recalibrate rattle finishes, give it another couple 
of seconds, just to be sure, then hit ctrl-reset. If you're not dropped 
into the monitor (showing a "*" as a prompt) then do a CALL -151 to get 
into it. Once there, take a look at memory from about $0803 on to $08FF.

If most of the gibberish you see as output from that is a pattern of "FF 
FF"s, alternating with 00s, then nothing is getting from the disk to the 
computer, and it might be the fault of the card, the drive, the disk, or 
all three. More testing is in order to see where the fault actually is. 
If there's proper boot code there, then the disk itself is suspect - The 
drive can read the bootstrap code, but can't proceed beyond that point 
for some reason. Perhaps due to blown/non-standard sector marks, 
corruption of the boot track, or who knows what else.

I can't take you much further than that for troubleshooting right now, 
but it's a place to start looking.

-- 
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
I respond to Email as quick as humanly possible. If you Email me and get no 
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