RD54 Stopped Spinning

Jon Elson elson at pico-systems.com
Fri Apr 3 11:26:24 CDT 2015

On 04/03/2015 08:17 AM, Johnny Billquist wrote:
> On 2015-04-03 09:58, Robert Jarratt wrote:
>> 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?
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.


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