Re: Apple 400k drive

Yes, I did think of that., but I want to keep a 400 drive in there if I can. If things don't work out, this is an option.

Terry
----- Original Message -----
From: "simon" <simski_at_email.domain.hidden> To: <lisalist_at_email.domain.hidden>
Sent: Wednesday, March 09, 2011 9:43 PM
Subject: Re: Apple 400k drive

> maybe you can get them from a newer 800k or 1.4 drive or even a pc drive.
> furthermore some motors in laserprinters use the same technique.
>
> On 9 mrt 2011, at 00:07, Terry Stewart wrote:
>
>> Hi Helmut,
>>
>> I'm not sure of the exact part description of the passive hall sensor.
>>
>> In the first instance, I'm going to try and identify which ones are
>> faulty, and mix and match so that out of two non-working drives I get at
>> least one that behaves as it should.
>>
>> Terry
>>
>> ----- Original Message ----- From: "Diogenes45" <helmut_post_at_email.domain.hidden>
>> To: "LisaList" <lisalist_at_email.domain.hidden>
>> Sent: Tuesday, March 08, 2011 9:48 PM
>> Subject: Re: Apple 400k drive
>>
>>
>> Hello Patrick,
>> and greetings from Helmut Post!
>> Do you remember me?
>> My third IDE File is running very well!
>> Back to the topic: What is the exact part description of the passive
>> hall sensor?
>> Perhaps I know a place where to get obsolete and very hard to find
>> parts.
>> Lately I purchased 2 Z8 processors (Zilog 8631) with 4 KB XROM for
>> the 10 MB Profile - these are very hard to get, but there are still at
>> least more than 40000 pieces left today. The price was $ 4.06 for
>> each part.
>>
>> Helmut
>>
>> On 8 Mrz., 08:24, PSchaefer <dr.p.schae..._at_email.domain.hidden> wrote:
>>> On 7 Mrz., 21:18, "Terry Stewart" <te..._at_email.domain.hidden> wrote:
>>>
>>> > I've been in discussion with folk on the classic computer mailing list
>>> > > about
>>> > this. The feeling was it could have either been the TA7259 motor >
>>> > controller
>>> > IC, the associated caps or on of the hall-effect devices in the motor
>>> > controller IC itself.
>>>
>>> Usually this is attributed to the hall effect sensors which get a
>>> voltage offset.
>>>
>>> With a good sensor, you can measure half the supply voltage at the
>>> outputs when no magnetic field is applied. The difference between both
>>> output terminals goes positive or negative, depending on the field
>>> direction.
>>>
>>> With a bad part, this signal is shifted towards the positve or
>>> negative direction. Therefore its zero crossing is not at the point
>>> where the controller expects it, which makes the signal unreadable.
>>>
>>> A drive with one faulty sensor will spin when started manually,
>>> otherwise it will do nothing or oscillate. With two broken sensor, the
>>> motor cannot operate at all.
>>>
>>> Up to now I did not find suitable replacements for the passive hall
>>> sensors used in the 400k drives.
>>>
>>> Patrick
>>
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> --
> Groeten,
>
> Simon
> simski_at_email.domain.hidden
>
>
>
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