
Originally Posted by
doorknob
The step signal should be a pulse. You probably will not see it on a multimeter. You may be able to use a logic probe, however I would prefer to use an oscilloscope to check that signal.
In fact, I'd check the step signal(s) at both the DB25 pins on the controller board and also on the "other side" of the optocouplers.
IIRC, some folks have mentioned that the optocouplers that come installed on the board have (too) slow a response time. If the step pulse is not making it through the optocoupler unmolested, then you will definitely have problems.
In fact, it is not inconceivable that different DB25 cables from the PC's printer port to the board could affect the shape of the step pulses in a manner that could cause problems.
I'm not sure where (in your software) you can set the duration of the step pulse - it may be that the only control is when you choose between, for example, 25 kHz operation or 40 kHz operation, or perhaps there is a separate pulse width parameter that can be adjusted.