Denford Software & Machines

The logic power enters the board on pins 4 and 5 and the motor supply on pins 1 and 2.

The drives are enabled by a logic signal from the control board and motion is created by sending clock and direction pulses.

If the drives are not enabled (can be turned by hand when the power is on) then it is either the enable issue or the power supply.

I think you have confirmed the power is OK so it looks like a fault in te enable circuit which could be on either card.

I'm not using the top board, just connecting directly to the 96 pin connecter on the bottom board.

So, Could it simply be that there is no enable signal present?

So, Could it simply be that there is no enable signal present?

I couldn't find an enable pin on the 96 way connector here:
viewtopic.php?f=15&t=2119
And have had it working myself without a top card just by connecting step and direction (viewtopic.php?f=4&t=2264)

However, I'm sure there is an enable to energise the steppers - whether it's just the dedicated stop input on the bottom board I'm not sure.
If there is a signal from the top board via the 96way then it could have been floating in the past and may work randomly (ie, it would need tying to GND or +5v)

Thank you; that possibility sounds worth exploring. I've scoured the pin out/in diagrams for the 96 way connector and the 50 way connector and can't find anything obvious that suggests an enable signal might be required. I will ask Baldor if they are able to offer any advice.

Failing this, I think I will have to look at replacing the Denstep card with an economical alternative. Probably something like a the Gecko G540, which looks like it might be suitable and is reasonably priced and idiot - proof; important for me

diycnc do a system 4 board which works well, and is cheap.

Talking of cheap steppers, I'd like to know if something like these would drive one of our machines:
https://www.pololu.com/catalog/product/1182
They are up to 16x microstepping, 5V logic and 8-35V and 2Amps to the motors ... and the A4983 can be bought for £10 ea

is that not just a carrier for the allegro chip. Would it need extra circuitry to be used as a driver, or just need a board to interface it.

After reading through it a bit more carefully it looks pretty complete. I would imagine to get the full 2amps you'd need a reasonable heatsink. The allegro chip has been used a lot with sub 2 amp drives.

Yep I think to run at 2 amps you'd need a heatsink and a fan.
But other than that you'd just need a simple distribution PCB to plug them onto with connectors for power, motors output, step+direction and jumpers to select microstepping mode...

i may get some of these and have a play.