Re: Apple 400k drive

no. i mean only the sensor of a 800k drive...

On 9 mrt 2011, at 09:58, Terry Stewart wrote:

> 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:
>> 

>>>> 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

>> 
>> --
>> Groeten,
>> 
>> Simon
>> simski_at_email.domain.hidden
>> 
>> 
>> 
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 --
Groeten,

Simon
simski_at_email.domain.hidden

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