Re: How do I check the MOSFET's in my stepper driver

Thanks Mariss,

No shorts :-)
Weird though, the A + and - read in the megohms, the B + and - read
in the kilohms. More than an order of magnitude difference expected?

Jeff



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
<mariss92705@y...> wrote:

>
> 1) Set your multimeter to Ohms.
> 2) Disconnect the motor and power supply from the drive.
> 3) Connect one meter lead to drive power supply ground.
> 4) Measure the resistance at each of the 4 outputs.
> 5) Move the lead from ground to drive + supply input.
> 6) Repeat (4)
>
> Transistors invariably fail shorted. If one or more of the 8
> measurements you took show a short then the drive has 1 or more
> damaged power transistors.
>
> Mariss
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "washcomp" <jeff@w...>

wrote:

> >
> > I blew a fuse in my API CMD-260 stepper driver. Before I put it
> back
> > into my CNC mill, I'd like to make sure that one of the MOSFET's
> > didn't blow and cause the fuse to go. How would I test them
> without
> > de-soldering? (I didn't find any consistancy in resistances with
> my
> > ohm meter, probably because of external circuitry or
> interconnection
> > between them). There are ten of them in there.
> >
> > Or should I just change the fuse and hope for the best?
> >
> > Jeff