3 Apr
2015
3 Apr
'15
10:06 a.m.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Jon Elson
Sent: 03 April 2015 17:26
To: General at classiccmp.org; Discussion at classiccmp.org:On-Topic and Off-
Topic Posts
Subject: Re: RD54 Stopped Spinning
On 04/03/2015 08:17 AM, Johnny Billquist wrote:
Yes, it is 6 transistors.
All this sounds like I am going to have to open up the disk to get inside as the motor is
on the inside. I don't think there is a way to turn the spindle without opening it.
Interestingly at one point it started working again. Then after I put it all back together
again, it stopped working once more. In one case, it seemed to start spinning when I
changed the disk's orientation (on its side rather than flat), almost as if it just
needed a mechanical encouragement to get it moving. But now, no matter how many times I
try, and what different orientations I try, it doesn't work. Does any of that help
with pointing the finger at all?
Regards
Rob
On 2015-04-03 09:58, Robert Jarratt wrote:
If six transistors, then it is brushless (I'm sure that is true). But, you
should
check the Hall sensors.
Likely one may have failed. There should be 3 sensors in the motor, at any
time they should be in a state where one is high and two low, or two high and
one low. So, turn the spindle while checking the 3 sensor signals, all should
cycle.
If the sensors are OK, then the logic going from the sensors through to driving
the power transistors is not working.
make sure the crystal oscillator is running, that regulates the motor speed
controller.
Bit of an update. I put the transistors back as
they seem to be OK
and applied power to see if probing around would show anything. The
Z8 was getting power, and the transistors did heat up within a few
seconds, but the disk did not spin at all. Is this going to be a
problem with the motor itself?
Brushes of the motor (if they have them) would be one thing to check.
Check if the motor is getting power?