Help with Starturn 4

[Greg G0XDX]

Help needed please

I've obtained a starturn 4 ,red model via ebay from a deceased sale so have no background info , its immaculate as a lathe the bed looks unused.

it has the slave board intact , spindle runs manually if a little slower than i expected i.e. it doesn't scream

Its been setup previously with a C11 BOB powered by a 5v wall wart to to the drive side , no 12v and usual usb to the pc side
only the x and z have been wired, no stops or spindle.

to do this previous owner had tapped the the step and dir directly from the c11 to a chip on the slave board and soldered directly to the chip pins , he then had a ground from the bob GND to the starturn metal frame.

I'm using Linux not mach and I couldn't get it to function effectively so I dispensed with that and reverted to the traditional transistor and 3.3k bias resistor ,I've removed the 4 step and dir wires from the edge of the slave board and connected the transistor board to them.otherwise the slave remains intact and powered as it has the relays integrated into it not the later separate board. I've taken the ground to his ground on the frame ,so the bob ground is direct to the starturn frame.

I can now get it to jog but only in one direction , if i reverse direction with the jog its dead ,same on both axis
using the same transistor resistor setup for the dir as step and all common to one ground rail
I'm at a loss as to why if anyone has any ideas .

Reading the manuals for the driver i think i can hotwire the internal oscillator to drive it manually to test things?
I'm assuming to reverse it i ground out the dir pin on the drive ,can i do that manually to test the drive ?

Can anyone give me the exact settings for Linuxcnc it requires ns or ns2 , various post here state various numbers but not the units they are referring to i.e. mm seconds inch or minutes . i suspect mach input units may not be in mm/ns.

I'm at the point where I'm looking at ripping the lot out and getting new Chinese drivers and steppers

Thanks

Greg

[Greg G0XDX]

update
Resolved most of my issues and have both axis running back and forth at speed . Simply the 0v wire from the bob that grounds the new transistors needs to go directly to the 0v on the drive itself not any ground on the machine frame . DC continuity says its the same but for whatever reason it wasn't for me. Take the step dir and 0V all to the driver pins direct and it lives. Now for the spindle control
Greg