[villamany]

at 13.8v i get some step stall, at 24v are very more step stall.

The stall are increase with:
- more steppers connected.
- with more torque settings.
- with more voltage.
- with less time decay settings.
- with low microstep settings.

Seems to be also noise problems.

What are the added resistors that i can see on "cntr_bot.jpg" picture?.

I only need 4x10k resistors, 1x74hc14 ic and 1x decouplig capacitor for these mods is ok?.

I has my controller working for about 5hours without problems on 12v regulator (very hot for my hand but not thermal shutdown ocurred).

[lasik2025]

at 13.8v i get some step stall, at 24v are very more step stall.

The stall are increase with:
- more steppers connected.
- with more torque settings.
- with more voltage.
- with less time decay settings.
- with low microstep settings.

Seems to be also noise problems.

What are the added resistors that i can see on "cntr_bot.jpg" picture?.

I only need 4x10k resistors, 1x74hc14 ic and 1x decouplig capacitor for these mods is ok?.

I has my controller working for about 5hours without problems on 12v regulator (very hot for my hand but not thermal shutdown ocurred).

villamany,

The 4 leaded resistors that can be seen on "cnr_bot.jpg" were my attempt to fix the controller by changing the STEP/CLOCK pull-up from 4.7k to 1.0k. I did this by leaving the 4.7k in place and adding 1k resistors in parallel between the +5v supply and the Step signal ; the resulting effective pull-up was 4.7k || 1.0k = 0.8k. On my board, the chip resistors and capacitors are glued and soldered down making removal of those parts a little difficult and I did not want to risk damaging any printed circuit board traces by applying enough heat to cause the glue to release.

For the mod's, you may want 6 resistors as you will not want to leave the unused 74HC14 inputs unconnected; you can tie them to ground or +5v or, as I would suggest, to pull-up resistors. That way if you come across another signal that needs buffering the you will have spare buffers in place.

To hold my (ver 1) buffer board to the controller I used double sided foam tape (see "bufbrdmntd.jpg - buffer board mounted").

I have attached a schematic for a ver 2 buffer board for your consideration.

[villamany]

many thanks, finally i am going to use 3 buffers for the 3 step pins and the another 3 buffers for apply the same fix to dir pins (my controller only has 3 axis ) for prevent purposes.

If i can measure the real osc capacitors value i let you know.