?Chuck, you report 3.5v output on the || port. While well within the IEEE specs, that may be a marginal voltage, and could explain why it only works intermittently. If your voltage is marginal, temperature changes are enough to shift the switching
threshold. || port voltages have historically been a problem with Mach, and were notorious with laptops.
It would be a little work, but you could test this with a breakout board. Just put a 1K pull-up resistor attached to a 5v rail on each output port.
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On Jan 18, 2024, at 1:46?PM, Chuck Kahler <chuck767@...> wrote:
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John,
I just tried changing the jumpers JP4 and that didn¡¯t make any difference. I then change the jumper on JP3 and again no improvement.?
When I say changed, I¡¯m talking about changing them from the default configuration. ?
For some reason, although I¡¯m getting the proper voltages on the parallel port pins, they don¡¯t seem to be having any effect on the PMDX board?
Chuck?
On Jan 18, 2024, at 12:28?PM, John Dammeyer <johnd@...> wrote:
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Hi Chuck,
On my PMDX_125 and 126 it¡¯s possible to jumper or disable the need for the charge pump.? To remove one more variable I¡¯d disable that.?
Once disabled see if the direction signals into the PMDX-122 are changing to the appropriate Gecko.? I¡¯m assuming the Gecko enable is working because you said
your motors were locked.
John
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I¡¯m still chasing gremlins, but I have some more information that may generate some new ideas.
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There have been a lot of inputs so far and I have addressed them with no joy.?
so here is where I am currently.
Summary:
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I have a PDMX- 122 and Gecko drivers on my Table top TAIG 4 axis milling machine. Using MACH3.?
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It¡¯s been running fine for years and then all of a sudden in the middle of a job it stopped.
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I checked the voltages for the direction pins on the XYZ axis And they each registered 3.5 V and 0.2V when checking the direction pins.
Does this voltage sound correct?
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I also checked the voltage on the charge pump, and it registered the same.
although I am getting these voltages coming out of the parallel port cable, I am not getting any voltage on the PMDX ¨C 122 board itself. When I try to move an axis.?
?
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From everything I¡¯ve checked so far the problem appears to be either in the PDMX ¨C 122 board itself or some setting in MACH3 that is not set properly.?
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Is there a way I can troubleshoot this board??
I have tried the PMDX forum, but it appears to be having a problem currently.?
any additional help would be greatly appreciated,
?thanks,
Chuck?
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