Re: testing SFD1001 spindle speed

From: Francesco Messineo <francesco.messineo_at_gmail.com>
Date: Wed, 12 Feb 2025 14:27:21 +0100
Message-ID: <CAESs-_zik1MVvjhWKTj+du-UomfSCt==+QEiGA6ESqRg_U2m4Q_at_mail.gmail.com>
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 15:00:32

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