4 Apr
2015
4 Apr
'15
2:06 p.m.
-----Original Message-----
From: cctech [mailto:cctech-bounces at classiccmp.org] On Behalf Of tony
duell
Sent: 04 April 2015 20:57
To: General Discussion: On-Topic Posts
Subject: RE: RD54 Stopped Spinning
is the
here the schematics of the XT 1140 from a basic
four manual
http://www.ardiehl.de/basicfour/download/mai2000/Maxtor_XT-
1140_Schema
tics.pdf
Thanks for that, it is something I have been looking for for some time.
Page 9 of that .pdf seems to show the spindle motor controller. My guess 3 signals H1, H2, H3 are the signals from the 3 hall
sensors in the motor.
I think
I would start by seeing what is there (look as though
they should be TTL
signals,
so easy to check) and also see what the Z8 is sending
to the motor driver
circuits.
Y1 is the clock crystal, see page 12 of that pdf. I assume it is
oscillating, do
you
see the expected 6MHz on pin 9 of U41?
I don't think it'll be possible (or at least not at all easy to replace
the
hall
sensors. My guess is that the angular position of the
platters is
critical and they
won't centralise accurately enough either.
So I would only dismantle the HDA as a (very) last resort.
-tony
=
So when I fired it up again with the scope, the disk started to spin. This
was a stroke of luck as I was able to probe what I believe were the outputs
of the hall sensors. All three oscillated, but one of them showed
significant sideways wobble on the scope, which suggests to me that the
signal is not absolutely regular. It does seem to suggest that one of the
sensors is not working well. However, would this be enough to explain why it
stopped dead in its tracks when it was working before?
Changing one of these sensors is probably going to be beyond me :-(
Thanks
Rob