Servo Board Failures

[CNC_Newbi]

Any tutorials out there or even personal experience on "Common Causes for Servo Board Failure"? My machine toasted two boards and I am proceeding cautiously before buying new ones.

[Al_The_Man]

What kind/make of servo's? DC motor? AC servo? PWM drive? SCR drive?
Al.

[CNC_Newbi]

Thanks Al,

DC Brushed servos. PWM boards.
Both made by Servo Dynamics (Named "Fenner" long ago).
Old school controller (Numericon 850?) >D/A boards > PWM servo drivers >Servos

[Al_The_Man]

I believe Servo-Dynamics were similar to Westamp? A popular PWM drive of some years ago, these were velocity type drives which required a tach on the motor.
These drives usually develop problems with aging components etc.
I prefer to replace them with A-M-C or Copley Controls and set them up in the torque mode, (no tach needed).
Or if the control will is not fast enough, they can be used in the volocity/tach mode if required.
Al.

[CNC_Newbi]

You are right Al, the units do use Tach as well as Encoder inputs.
Is my best bet to dump the controller and use a PC w/Mach3.
Dump the D/A boards and Drive boards and go with the Copley/AMC units? Digital or Analog? Could the controller have killed the boards? The servos? Just heat & heavy use on old electronics?

[Al_The_Man]

It may not need anything as drastic as that if the control is still OK, you may want to consider trying an amp conversion first, they are analog input, Mach3 is step and direction.
Al.

[CNC_Newbi]

So dump the D/A boards & the drive boards and replace with new analog boards? If that doesn't solve the issue will those boards be usable with a Mach3 system? Is there another controller option at a reasonable cost?
How would I know if the controller is OK?
Could It have damaged the boards?

[Al_The_Man]

Unfortunately analog drives do not work with mach3 unless you get a step/dir to analog converter board.
Controllers generally are not the cause of drive failures.
Al.