I smoked my Acorn - Is It Junk?

[wdannhardt]

Greetings fellow Acorn users, and thanks to all who provide feedback on this forum. It's an incredible resource. I've been referencing several threads here and it got me ALMOST to the finish line.

Setup:
-2 axis lathe conversion from 12" Chinese 12x36
-Acorn Rev 4 (14455)
-CNC12 Lathe Version 4.20.1
-DYN4 servo's w/ 750w motors
-link to photo album: https://photos.google.com/album/AF1QipP ... GNOzoOUM7U
-Report attached

Initial setup went easy and mostly worked. I had a strange intermittent servo motor motion problem that was being caused by the DMM cables (w/ dropping resistor). I solved this by soldering a jumper across the DMM resistor, and connecting 5V to the brown wire on the cable. This essentially makes the connection the same as the S14888-ACORN_rev3 DMM DYN4 SERVO DRIV schematic. See pic below of red jumper wire.


After getting this working, I was snapping the plastic covers back on to the DB25 connectors when I accidentally grounded one of the pins with a screwdriver and created a ZAP! I had removed the power to the drives, but forgot to power off Acorn. STUPID!

So it looks like I fried something on the board that controls Axis-1. Axis-2 still works. I swapped cables and drives and confirmed that the problem is the Acorn output for Axis-1. Is there anyway to check these outputs with a multimeter?


Assuming that the Axis-1 is dead, is there any way to turn off Axis 1 and use Axis 3 instead? I tested Axis 3&4 and both still work. So instead of (Axis-1 = Z / Axis-2 = X), I would have(Axis-2 = Z / Axis-3 = X) The wizard will not let me set Axis 1 to N.



Also, I came across a thread where someone used the DB25 output from Acorn instead of the ring terminals. There even looks to be a way to re-map the pins. Unfortunately, I can't get any motion when I use the DB25. It provides step and direction, but not the enable signal.

Any suggestions are appreciated.

Walt

[briuz]

Well, I can't see your pictures but had something similar happen to me earlier this year.

On the CNC lathe I am building, I had a wire come loose on one of the stepper motor drivers. My belief is that it shorted out and damaged my Acorn V3. After some testing I discovered that the direction no longer worked on the axis that had the loose wire.

So, after exploring my options I decided to take a gamble. There are a couple IC's that connect to H2 and H3. The digikey part number is TBD62083AFGELCT-ND. So, figuring I had little to loose I bought a few of these chips for around $1.32 each and replaced the chip that connected to the offending pin. (Well, it wasn't quite that easy as it's surface mount and I watched a video on how to solder it on, as well.) For me, this worked and the board is now doing well.

[wdannhardt]

Thanks for the suggestion. If all else fails, I might give this a try. Question: how did you diagnose the direction signal as the problem?

Below is an updated link to my Google Photo album. Hopefully this one works.

[briuz]

I noticed the problem when the direction wasn't changing on the axis. (It worked before.) After checking the wires, I found the direction wire was hanging and re-installed it. But there was still no change. So, I tried another Gecko stepper motor driver board (that I knew to be good) and there still wasn't any change. That left the acorn board.

I looked closely at the Acorn board and found that the stepper motor driver connections were all connected to the TBD62083AFGELCT-ND chips and those chips look like some sort of interfacing switch. Having nothing to lose and with the chips being cheap, I swapped out the chip connected to the offending direction line and it worked.

[GBCues]

If you finally determine that you've trashed your Acorn, somewhere on Centroid's website, there is an offer for a discounted board for folks in your same situation. It's kind of buried, so you'll have to do some searching.
Good luck
Gary

[martyscncgarage]

https://www.centroidcnc.com/centroid_di ... ranty.html
$199 swap out program

Happens to the best of us. Expensive lesson learned.
It is possible you could use the DB25. It stands at 5VDC logic.
Order a DB25 male breakout board from Amazon.
The problem is your enable is not on the DB25

Marty

[wdannhardt]

Thanks guys. I feel 33% better