Re: [CAD_CAM_EDM_DRO] Gecko failure/repair

Chris,
It has been my experience that Power FET's do not handle shorts.
if you think that is what happen then there is a good chance the the
MOSFET is gone.
You can replace it and then check to see if anything else failed by
hooking it up and trying it out.
This has worked for me in the past.
It is a good idea to keep a few extra FET's around anyway.

Dale

On Wednesday, March 26, 2003, at 11:13 AM, resosys wrote:

> Greetings,
>
> I'm hoping someone has some wisdom on a particular problem that's
> developed with one of my old style Gecko 201 stepper controllers.
>
> Symptoms:
>
> The motor vibrates back and forth as if one of the phases is not
> working.
> Replacing the stepper controller with the other axis' controller
> results in proper operation (motor and wiring are correct).
> The "failed" Gecko powers up and responds to step and direction
> signals.
>
> It seems as though one phase output was blown. There are no burn
> marks or blown parts on the top of the board that I can see. Since
> these are the open case selloff units with no warranty, I removed the
> heatsink/mounting plate and examined the drive FETS. One of them next
> to the mounting screws shows a slight burn mark on the leads.
>
> It may be possible that my motor leads shorted and popped the output
> for that phase since I found a loose wire on one of the pins on my
> motor connector.
>
> Questions:
>
> Has anyone seen this behavior?
> Are there any specific tests to perform?
>
> I have the parts here to repair the unit, if it's possible. I'm
> hoping someone has seen this issue before and can tell me what damage
> was done so I can get a head start on troublshooting and repair.
>
> Thanks in advance for any help.
>
> Chris
>
>
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