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

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