tb6560 controller problem

I bought a Chinese CNC 4030 a couple of years ago and have been using it without any real problem until recently when the controller board blew one axis controller.
I replaced it with the tb6560 3-axis controller and got it set up and working...BUT... it will only work at very low speeds, it's like it has no torque and is mossing steps even without any load on the machine (not cutting).
I've read through all settings and can't work out what is wrong. It is using the original Chinese Steppers but they worked fine with the old controller which was a lower current maximum.
Any help appreciated, thanks

There is no "the tb6560 3-axis controller", there are dozens of the buggers knocked out by all and sundry in China! ;-)
Photos and links including product specific documentation will help the class address your questions. :D
You can buy the TBxxxx chips very cheaply, have you considered fixing your original board?

Another thing to consider when replacing a 3-axis board when one axis fails is to buy separates - a BOB and 3 single axis controllers + 1 spare, then when you pop an axis you have a swap out and/or can use working parts from one axis to identify the exact location of the fault on another,
Regards,
Nick

Just a thought - have a look at the step/direction pulse width within Mach3 (if this is what you're using). Fiddle the value to be longer (e.g. 5us) and see if this helps any.

Thanks for the reply's. In true fashion, I finally gave in and asked then went back to it and tried more things. I changed the step setting to 1/8 from 1/16 and slowed it down considerably (although the old speed setting worked with the original controller) and got it working. I will try changing the pulse widths too as I'm still not 100% with it right now, although it is getting things cut for now.
More settings testing to follow....