Re: [CAD_CAM_EDM_DRO] Re: testing with multi-meter - GECKO

andrewyslee wrote:

>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
>
>>Disconnect the wire to terminal 9, and see if it starts going from
>>
>>
>low to
>
>
>>+5 V. It should go somewhere between .4 and at least 3.5 v with no
>>
>>
>load.
>
>
>>Terminal 9 of the Gecko should go to roughly 5 V, assuming the +5 V
>>is still hooked to "common".
>>
>>
>
>Driver not with me now, but in earlier tests, parallel cable
>disconnected produced the following readings.
>terminal 9 (step) 4.89V all axes.
>
>What does this signify? Does that mean the optoisolator is still OK
>or bad?
>
>

It is not a clear indication. If it was 0 V, that would be clearly bad
- an open resistor
or LED. If your DVM has a diode test position, check between common and
step.
It reads voltage with some small current applied. You should read about
3 - 3.5
V one way (reverse biased, LED not conducting) and about 1.8 - 2.4 V the
other
way (forward biased, LED conducting, with resistor in series). Compare to
the direction channel, they should be the same.

If the above test looks OK, then you must have a bad cable or bad
parallel port.

Jon