Re: 8050 which will write but not format

From: Rob Clarke <>
Date: Sat, 01 Dec 2012 01:47:58 +0100
Message-ID: <>
Hmm, thanks Julian - I have checked and adjusted the speed with the 
8296D diagnostic tool and it claims they are bang on. It also measures 
the variation, which it also claims is OK. Should I have reason not to 
trust it?


On 01/12/2012 01:41, Julian Perry wrote:
> Rob
> You will get that problem if the drive spindle is running to fast.
> Julian
> Saturday, December 1, 2012, 11:17:18 AM, you wrote:
>> Gents,
>> I would not normally post 'please help me fix' type questions here but
>> this one has me stumped. Some may already have seen the thread on
>> vintage-computer forums here:
>> In a nutshell, drive 1 works 100%, drive 0 will read and write but not
>> format. It usually stops on track 1 with a #21 read error but
>> occasionally will go as far as track 3 or 4. If I swap the mechanisms,
>> the problem stays with drive1. This implies a problem in the analogue
>> board (micropolis pcb #8050006) but I can't find it and I don't
>> understand what kind of problem would allow it to write but not format.
>> I know the mechanisms are good and well aligned and, as the drives read
>> OK, they are properly speed adjusted.
>> Do any of you disk wizards know the algorithms by which these drives
>> format a disk? I hoped this might give me a clue.
>> Rob
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Received on 2012-12-01 01:00:53

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