Centroid Community CNC Support Forum

This is a post for posterity, whenever I have a problem with something, I search for similar issues that others may have experienced, hopefully to find a solution.

I finally fixed my Adtech QSAA015M servo driver and 20 seconds later the replacement that I had ordered for it arrived (I think that's called Murphy's law).
Anyway, here is a rundown of the cause and the fix.

1/ I (foolishly in hindsight) assumed that the Acorn controller would be exactly the same as my Ethernet Smoothstepper that I had been using with Mach3, so I didn't do much checking of my old setup (mistake 1).
2/ I connected 24V signals (step, Dir etc) where I had previously used 5V signals (mistake 2) I could easily have fixed this by adding resistors.
3/ I reversed the polarity of said signals because, for some reason I thought this was the right thing to do (severe mistake 3).

My gung ho attitude, led to a damaged servo controller (Dir signal wouldn't work) and numerous forum posts asking for help.

The damage to the controller was as follows:
A surface mount resistor (210 ohm) on the input of the "Dir" signal measured as a short, because it had overheated and melted the solder underneath. This was fixed by removing the 210 ohm resistor and resoldering.
A 6N137 opto device was open circuit on the input side. This wasn't apparent when measured "in circuit" because there was another diode in the circuit as well, so it was only after I removed the 6N137 from the board that the damage to it became apparent.
Repairing these issues fixed the controller.

What did I learn from this other than the obvious? Well not much really, I have an impetuous nature, which will probably get me killed one day....

Dave

Dave its called a right of passage. We all domit...eventually.
Bottom line, are your drives turning motors now?
Marty

Yes, I can turn my servos happily with the Acorn now Marty. I'm still waiting for my spindle encoder to arrive, but the carrier says they will deliver it tomorrow. After that it's full steam ahead. Based on past experience I now know for sure that it will be smooth seas and fair sailing from herein.

I repaired the damaged resistor on the servo controller, and replaced the optocoupler on the servo controller. The Z: axis still wont change direction using this servo drive, but the X: axis will reverse using the same servo drive. I strongly suspect that the Acorn is damaged.

dmbgo wrote: ↑Thu Sep 17, 2020 11:51 pm I repaired the damaged resistor, and replaced the optocoupler. The Z: axis still wont change direction using this drive, but the X: axis will reverse. I strongly suspect that the Acorn is damaged.

You mentioned in a previous post motors were turning well....
Move the offending drive to a different axis and see if the problem stays with the drive or stays with the axis output on Acorn. You did not describe what you did and how you tested it.

dmbgo wrote: ↑Thu Sep 17, 2020 11:51 pm I repaired the damaged resistor, and replaced the optocoupler. The Z: axis still wont change direction using this drive, but the X: axis will reverse. I strongly suspect that the Acorn is damaged.

IIRC, the output drivers on Acorn are fairly low current open drain transistor arrays with no protection, so a short circuit with a 24V supply probably wouldn't do any good. Should be simple enough for you to replace it.

Look at the top of this page for some info about the Toshiba D62083AFWG driver ICs. viewtopic.php?f=60&t=4724&p=39707#p39707

Here is my other post on this subject, I am including it here for the sake of completeness.
"Z axis not getting a Dir signal
Post by dmbgo » Fri Sep 18, 2020 1:39 pm

I blithely assured Marty that my problems were solved, my motors were turning and I was just waiting for my lathe spindle encoder to arrive in order to start setting up the VFD.
I was wrong, I still have a problem with my Z axis.

The Z axis spins the servo nicely, but doesn't reverse direction. This is still a bench test, so I am able to just swap the cable into the X position and see that the X: axis turns in both directions, wheras the Z: axis continually turns in one direction only (anticlockwise).

Just to make things clear, if I use the MDI and type G0 X50 and press start, the X: axis turns anticlockwise, if I follow this with the MDI command G0 X 0 and press start, the X: axis turns clockwise.
if I swap the cable over and continue to use the same cable and servo motor, and use the MDI to type G0 Z50 and press start the Z: axis turns anticlockwise, if I follow this with the MDI command G0 Z 0 and press start the Z: axis continues to turn anticlockwise.

I have used a DMM to measure the voltage on the Dir terminal of the Acorn board for the X: axis and it toggles between 0v and 24v, as I change direction. The Z: axis doesn't, it stays at 24v no matter which direction is commanded.

I suspect (strongly) that when I initially miswired the servo controller, which damaged the servo controller, and which I have now repaired, I must have also damaged the Acorn board.
I am hoping that the Acorn outputs are protected by optocouplers, are they? Also is there a circuit diagram of the Acorn board somewhere?
Sorry to bother you again

Dave"

Muzzer wrote: ↑Fri Sep 18, 2020 1:22 pm

dmbgo wrote: ↑Thu Sep 17, 2020 11:51 pm I repaired the damaged resistor, and replaced the optocoupler. The Z: axis still wont change direction using this drive, but the X: axis will reverse. I strongly suspect that the Acorn is damaged.

IIRC, the output drivers on Acorn are fairly low current open drain transistor arrays with no protection, so a short circuit with a 24V supply probably wouldn't do any good. Should be simple enough for you to replace it.

Look at the top of this page for some info about the Toshiba D62083AFWG driver ICs. viewtopic.php?f=60&t=4724&p=39707#p39707

Just to be clear Muzzer, the issue described is on the main Acorn board, which I will look at again this morning. I am guessing that the Toshiba D62083AFWG driver ICs are on the main Acorn board? I will familiarise myself with them and see if I can locate the same this morning.

TBD62083AFG is the full part number of the driver IC Muzzer. Strangely a Google search doesn't return any results for D62083AFWG. Your link in the post to which you referred does take me to the correct part however.
I tested my board this morning and pin 14, labelled as O5 (I think this stands for output 5) isn't changing from +24V, when the direction of the attached motor is reversed. Pin 17 (or O2) is changing from +24V to 0V, when the direction of the attached motor is reversed.
This leads me to conclude that you have correctly diagnosed the issue it's probably the output of the driver IC. I have ordered some ICs this morning.
I haven't checked the input signal to the driver, but for the time being I think I'll assume it is Ok.