Re: Apple 400k drive

Update: I now have a working 400k drive for my second Lisa!

I'd like to say I fixed one of the ones I had but no. I did take a look at the hall effect sensors with a scope but there was nothing inconsistant I could see in either of the drives? No, it was John Woodall to the resuce. John sold me the X/Profile emulator. He generously donated some spare drives he had for the project...cost was shipping only.

THANK YOU John!

Two of the drives seem fine, so I even have a spare!

So, I've now got two Lisa's up and running, a Lisa 2 and a Lisa 2/10. It would be nice to find a working Profile to turn the Lisa 2 into a Lisa 2/5 but I think that might be wishful thinking (-:

The resotoration project's not quite over. I need to by some rubber feet for the Lisas and the keys on one of the keyboards are a kind of olive green colour. Time for a retr0bright soak I think. Then I'll be done.

I'll write up the a summary and take some pictures for my blog. I'll post a link here when it's done. Thanks to everyone on the list that made helpful comments. The Lisas have been both challenging and fun to work on.

Terry (Tez)

On Mar 10, 6:45 am, "terry stewart" <te..._at_email.domain.hidden> wrote:
> Oh I see.  Sorry, I misunderstood.
>
> Good thought.
>
> Terry
>
>
>
> ----- Original Message -----
> From: "simon" <sim..._at_email.domain.hidden>
> To: <lisalist_at_email.domain.hidden>
> Sent: Thursday, March 10, 2011 1:26 AM
> Subject: 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" <sim..._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_p..._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
>
> >>>> --
> >>>> -----
> >>>> You received this message because you are a member of the LisaList
> >>>> group.
> >>>> The group FAQ is athttp://lowendmac.com/lists/lisa.html
> >>>> To post to this group, send email to lisalist_at_email.domain.hidden
> >>>> To leave this group, send email to
> >>>> lisalist+unsubscribe_at_email.domain.hidden
> >>>> For more options, visit this group at
> >>>>http://groups.google.com/group/lisalist
>
> >>>> --
> >>>> -----
> >>>> You received this message because you are a member of the LisaList
> >>>> group.
> >>>> The group FAQ is athttp://lowendmac.com/lists/lisa.html
> >>>> To post to this group, send email to lisalist_at_email.domain.hidden
> >>>> To leave this group, send email to
> >>>> lisalist+unsubscribe_at_email.domain.hidden
> >>>> For more options, visit this group at
> >>>>http://groups.google.com/group/lisalist
>
> >>> --
> >>> Groeten,
>
> >>> Simon
> >>> sim..._at_email.domain.hidden
>
> >>> --
> >>> -----
> >>> You received this message because you are a member of the LisaList
> >>> group.
> >>> The group FAQ is athttp://lowendmac.com/lists/lisa.html
> >>> To post to this group, send email to lisalist_at_email.domain.hidden
> >>> To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
> >>> For more options, visit this group at
> >>>http://groups.google.com/group/lisalist
>
> >>> -----
> >>> No virus found in this message.
> >>> Checked by AVG -www.avg.com
> >>> Version: 10.0.1204 / Virus Database: 1497/3492 - Release Date: 03/08/11
>
> >> --
> >> -----
> >> You received this message because you are a member of the LisaList group.
> >> The group FAQ is athttp://lowendmac.com/lists/lisa.html
> >> To post to this group, send email to lisalist_at_email.domain.hidden
> >> To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
> >> For more options, visit this group at
> >>http://groups.google.com/group/lisalist
>
> > --
> > Groeten,
>
> > Simon
> > sim..._at_email.domain.hidden
>
> > --
> > -----
> > You received this message because you are a member of the LisaList group.
> > The group FAQ is athttp://lowendmac.com/lists/lisa.html
> > To post to this group, send email to lisalist_at_email.domain.hidden
> > To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
> > For more options, visit this group at
> >http://groups.google.com/group/lisalist- Hide quoted text -
>
> - Show quoted text -

-- 
-----
You received this message because you are a member of the LisaList group.
The group FAQ is at http://lowendmac.com/lists/lisa.html
To post to this group, send email to lisalist_at_email.domain.hidden
To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
For more options, visit this group at http://groups.google.com/group/lisalist