Re: testing SFD1001 spindle speed

From: Mike Stein <mhs.stein_at_gmail.com>
Date: Wed, 12 Feb 2025 10:43:26 -0500
Message-ID: <CAHHfo1u3HzD0eoWAdYhPyTkz_gyeo5VaQ0cde0yfvOsqd9=7cw_at_mail.gmail.com>
I just downloaded, printed and trimmed a strobe disk image and glued it to
the back of a fridge magnet.

On Wed, Feb 12, 2025 at 8:28 AM Francesco Messineo <
francesco.messineo_at_gmail.com> wrote:

> On Wed, Feb 12, 2025 at 2:17 PM <groepaz_at_gmx.net> wrote:
> >
> > Am Mittwoch, 12. Februar 2025, 14:03:34 Mitteleuropäische Normalzeit
> schrieb
> > Francesco Messineo:
> > > Hi all,
> > > I've just recapped a Panasonic JU-570-2 with horribly leaking
> > > capacitors that ate a few traces on the spindle PCB. Now before
> > > assembling back the SDF-1001 I wanted to test and correct the spindle
> > > speed if needed. However the drive motor doesn't have the strobo
> > > patterns, so an alternate method must be used. Does anyone know if any
> > > of the programs on the test/demo disks can help? Images as many of you
> > > know are here:
> > > https://www.zimmers.net/anonftp/pub/cbm/demodisks/drives/index.html
> > > Does anyone know any test point on the spindle PCB? I think pin 6 of
> > > the motor controller IC could be a good place to look, but I figured
> > > out someone must already know how to do this task.
> > > Thanks in advance.
> > > Frank IZ8DWF
> >
> > Perhaps you can adapt one of these programs to the sfd:
> >
> > https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/drive/rpm/
>
> thanks, those could be a good starting point indeed :)
> I think the only one that could be suitable is rpm3 (with or without
> changing the target track formatted) since the other two need properly
> formatted disks that I don't have (yet).
>
> However (full disclosure), the JU-570 mechanics has the index sensor
> and the control board isn't using it, so I can add a little resistor
> to Vcc to read the pulses (phototransistor wires are coming to P1
> connector) and use a time interval counter (200 ms is the nominal
> pulse interval). I was just hoping there was a faster way.
>
> Frank
>
>
Received on 2025-02-12 17:00:02

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