PERQ T2

[Allison]

>
>Subject: Re: PERQ T2
>   From: ard at p850ug1.demon.co.uk (Tony Duell)
>   Date: Thu, 02 Aug 2007 19:54:44 +0100 (BST)
>     To: cctalk at classiccmp.org
>
>> 
>> Hi Tony,
>> 
>> Thanks for the reply.
>> 
>> The drive is a Micropolis 1303, and I think it has
>> failed. The
>> drive does spin down after a minute or so.
>
>You know, it's really hard debuggin a machine when you're not told all 
>the symptoms :-)
>
>More seriously, this does sound like the standard Micropolis 1300-series 
>problem, when that rubber bumper goes sticky and prevents head movelemt. 
>The bad news is that all Micropolis 1300s (and their ESDI equivalent?) 
>suffer from it, or at least if they don't they will soon.
>
>Finding a replacement 1300-seires is probably not the wisest thing to do, 
>therefore.
>
>I've never tried it, but I have heard that people have had some success 
>in openign up the HDA *yes, outside a clean room), removing the bumper, 
>shutting the whole thing up and using the drive as normal. How long it'll 
>keep working is anohter matter.

I've done it three times and two are still running over 8 years 
and many thousands of hours later.

I'ts been done by others.  


Allison

>> 
>> I noticed the PERQ manuals do state that the hard disk
>> must
>> be able to perform a "locate disk heads" operation,
>> even
>> for a floppy boot - which I assume means find track 0.
>
>I beleive the hard disk must og 'Ready' Quite what that means I will have 
>to check -- the boot ROMs check for a particular state in one bit of a 
>particluar port. I candig out the EIO and DIB schematics to find out just 
>waht that means if you like.
>
>> Hence
>> I'm unable to boot from floppy.
>> 
>> I will check the signal levels just to be sure.
>> 
>> Wondering where to go from here. I'm guessing I could
>> buy a 
>> replacement 1303 drive - but they are not cheap (hence
>> my
>> other posting) just to try and see.
>
>Any reason not tu use some other ST412-interfaced drive? The PERQ _can_ 
>use it. 
>
>-tony