RE: CBM900 hard disk timeout

From: Martin Hoffmann-Vetter <>
Date: Fri, 24 Oct 2014 03:14:22 +0200
Message-ID: <009201cfef27$e00aa230$>

>> So it's possible the pcb from the MiniScribe disk isn't okay. You
>> have checked the stepping logic. At this time you miss the pulses at
>> the INDEX line. Is this signal present with the working disk? If you
>> see the pulses, you can analyse where the signal are generated. This
>> signal must be pulse once at one rotation!    
> No. I have scoped the ST-4096 I am currently using, and it also does
> not seem to send the INDEX signal.

Which level can you meassure? If it's low, because there is a missing pullup on the controller? Many signal are only open collector. The input side muß pull up the signal!

> So apparently it's not the problem for the controller.

That's the question. It's possible we have more then one error ...

>> The MiniScribe 3650 and 3675
>> (
>> has an error code 4 for the case "Index pulse not detected during
>> spinup". And the code 4 means:   
> Yes. I have seen this error being flashed when the drive fails to spin
> on powerup, which it does quite often. Combined with a screeching
> sound it generates on some occasions when spinning,

Okay, so the drive is successfully started. But you have trouble to read. Have you scoped the data line?

> I think this disk just needs to be written off :-)

Or newly formatted ...  8-(


       Message was sent through the cbm-hackers mailing list
Received on 2014-10-24 02:00:03

Archive generated by hypermail 2.2.0.