KX3 Spindle Problem

**ModelSteamKen** · 13-03-2020

Have owned a KX3 for some years now and I'm having no spindle rotation for the second occasion. The provblem was sorted by the late John Stevenson and at that time I replaced the spindle motor control board. The problem has happened again and going through the same test proceedures as before I find that I am not able to get anywhere 10 volts out of the breakout board. I have tried changing step pulses, pulleys and have the voltage adjuster turnned up full and can only get 4 volts. Is my problem in the breakout board this time or is it the motor control board again. X,Y & Z are working normally.

**JAZZCNC** · 13-03-2020

We need more info. I'd guess the BOB generates the isolated 0-10v and feeds this to the Spindle control board which I'd guess is a DC motor controller.

However, I'm guessing so it would be best if you could give more info and post pics of what's inside.! . . . . . Or because Basic BOB's are so cheap these days just swap out the BOB.!

**ModelSteamKen** · 14-03-2020

Hi Jaz
Yes the 0-10v comes from the BOB in the right hand side electrical compartment and then goes to the DC spindle control board in the rear compartment. All the works are as the standard Sieg KX3. I'll take some photos and post them to-morrow.
Thanks
Ken

**JAZZCNC** · 14-03-2020

Originally Posted by ModelSteamKen

Hi Jaz
Yes the 0-10v comes from the BOB in the right hand side electrical compartment and then goes to the DC spindle control board in the rear compartment. All the works are as the standard Sieg KX3. I'll take some photos and post them to-morrow.
Thanks
Ken

Ok well that's simple enough to check. Disconnect the wires going to the Spindle control board and measure the voltage at commanded speeds. If you haven't changed any of the Spindle settings in control software (mach3 I presume) then you should get 10v at full commanded speed. If you don't then it's the BOB at fault not the spindle control board.
If you have changed the spindle settings then I can't help anymore without knowing the BOB your using, but Knowing John S it won't be anything too fancy as he liked to keep it simple and cheap.

**ModelSteamKen** · 14-03-2020

Hi Jazz
Having problems putting a photo on but have checked the voltage and only getting 3.9v at full command speed. All setting are at original settings.seems like it is probably is a BOB fault.There is an web site visible on the board www.cnc4pc.com. Any other suggestions as to a make of board.
Ken

**JAZZCNC** · 14-03-2020

Good old John S probably just saved you some money by fitting decent gear.?
I think that's old or should say, early C11 board.? If you notice the board is full of plug-in chips rather than surface mount like many cheaper boards use, this is done so can easily swap them out if one blows up.

Cnc4pc is owned and run by a guy called Arturo who's a very helpful guy so maybe worth dropping him an email. He'll tell you which chip you need and more than likely sell you one.

**ModelSteamKen** · 14-03-2020

Hi Jazz
Thanks for the info I'll try and get in contact with Arturo at cnc4pc.
Ken

**Clive S** · 14-03-2020

Originally Posted by ModelSteamKen

Hi Jazz
Thanks for the info I'll try and get in contact with Arturo at cnc4pc.
Ken

Jon swift on this forum seems to collect a lot of bob schematics and might be able to help.

**ModelSteamKen** · 06-04-2020

Hi Folks
Still chasing the problem of having no spindle. I've been working with Aturo at cnc4pc but have had little sucess. The only board that hasn't been replaced is the small AP2 board which lies between the BOB and the main motor board. All the necessary voltages are now coming out of the new BOB to the connections at the board. Does anyone know what this sall board does and if outputs can be tested? Getting new AP2 board being hampered by present world situation.

Thanks
Ken