Sudden lost of Y2 slave control

Hi all;

My question is simple. No changes have been made to wiring or configuration, yet Y2 stopped working. I verified connectivity between the motor and the breakout board, all is good. I next tried swapping the plug position between my A axis and the Y2 axis, modified the hal file to reflect the swap and restarted LCNC. Now the X axis has joined the problem. Z still responds correctly.
What is more likely, a failure of my MESA 7i76U driver board or the breakout board or both?

Kind Regards,

On a 7I76U, if any of the 0..3 stepgen STEP or DIR outputs on TB2  have been
damaged, all 4 may be affected as they are driven by the same chips.
(U8 = 74ACT540  for the - outputs and U12 = 74ACT541 for the + outputs)

Thanks PCW;
Would it be more cost effective to replace the board or have it repaired?

Kind Regards,

You might do a simple output voltage check with no load to make sure the issue is with the 7I76U card

All  step/dir outputs should measure very close to 5V or 0V. nay on between voltages suggest a damaged
output driver chip

Mesa can repair the card for a nominal charge but shipping will add up.

Good morninig PCW;

Checked the voltages at the micro-stepper plugs this morning, all read either 0 v or 4.12 v, nothing in between. Although the high voltage is a bit low, I think it is within operational range. I'm not using an external 5 v supply for the board, though I have one to run my crosshair laser, so I could tap that supply if necessary. All of my dedicated power supplies 5, 12, 24 and 36 v are spot on their output voltages.

Not sure if it is the 7i76U or the 6i25 FPGA, which is configured as a 5i25, in the computer or something else that could be the issue. What is your suggestion at this point?

You might try measuring at the 7I76U with the plugs removed
though 4.12V sounds OK under load. (its really marginal with no load however)

I can post a program a bit later today that will toggle all the step/dir outputs
slowly for a more complete test.

Here is a little test program that slowly toggles all step/dir outputs so both states of all outputs
can be checked with a voltmeter:

 

You will need to

chmod +x 5i25stepgens.txt

then

sudo ./5i25stepgens.txt

and all step/dir outputs should toggle at a ~ 1/3 hz rate
 

After updating the mesaflash app, I tried starting mesaflash. No errors were reported, however, the output were not toggling. Checking the man page, I could not identify any option to keep the pins toggling until the app was cancelled. Since the electronics are located on the back of the machine it requires more that 1-3 secs to move from the keyboard to the board to measure the outputs. Checking currently running programs (ps -ef | grep mesa), no app containing the string "mesa" was running. Is there a hidden option that will keep the app running until cancelled?

However, checking all of the outputs, all voltages were sitting at 4.92 v. What are the next steps for diagnosing issues with the 7i76U?

Kind regards,

The step/dir outputs should continue toggling indefinitely.

At this point I would ask for a RMA# from Mesa and return both the 7I76U and the FPGA card for
analysis/repair/replacement.