RD54 Stopped Spinning

Jon Elson elson at pico-systems.com
Sun Apr 5 19:48:02 CDT 2015

On 04/05/2015 04:40 PM, Robert Jarratt wrote:
> I tested each FET using a component tester (Peak DCA55) 
> and it appeared to show that they were all good. I believe 
> they are FETs because the XT-1140 schematic someone posted 
> shows FETs and the component tester also reported them as 
> FETs. I do wonder if one of them is only partially 
> working, I seem to remember that the one you point out as 
> having smooth ramp was indeed the one with the wobble. If 
> I have further trouble I will follow Tony's suggestion and 
> swap them around to see if the wobble moves, but detaching 
> them from the heat-sink looks to be difficult. Regards Rob 
I'd just get some FETs that are compatible (probably MUCH 
better parts available today) and replace any suspect ones 
with new units. Are these pop-riveted to the heat sink?  I 
vaguely remember a drive built like that.


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