Tic T825 Troubleshooting

[Vinnie]

Recently purchased 2x Tic T825 to control Nema 17 Stepper motors via Raspberry PI. I’m in awe, how well these controllers work: seamless integration, easy-to-understand libraries, etc. and was able to get the robot running within a couple days.

Hardware:
Tic T825 Firmware Version 1.06 (Qty 2 in parallel)
Raspberry PI 4 (connected via USB port)
External Power Source: 12V 3A limit
Nema 17 1.5A 12V Stepper Motor (2x)

Setup:
Max Current 1472 mA (both motors were cold, wasn’t stressing them)

Been testing the actuators/robot for about 2-3 working hours and suddenly one of the Tic 825 suddenly stopped registering on Raspberry PI (error popped up: “Device ID: ######” is not connected) so upon a closer look at the LEDs one of the two Tic controller didn’t light up. I measured the voltage of across the wire terminals and registered 12V (both controllers were running parallel on the external power supply).

I removed the T825 that is having issues from the robot and plugged it directly into my computer via USB but nothing was turning on (no LED lights and doesn’t show on Tic Control Center). Just to make sure, I did it with the other Tic Controller but everything was working on this one. I’m a bit perplexed why one controller stopped working while the other controller was working just fine.

What can I do to verify the T825 circuit and if it got fried/manufacturing defect? and if there is potential to fix it?

[BrandonM]

From your description, I do not have any obvious leads as to what went wrong. Just to clarify, if you disconnect everything from the Tic, and just connect the USB to your computer, do you see any signs of life from the Tic (e,g, LEDs blinking, registering in the computer’s Device Manager)? If not, could you try measuring the voltage on the 5V(out) pin? You could also try a different USB cable just in case something went wrong with the one it was using.

Did you notice anything suspicious when the Tic stopped responding (e.g. a burning smell, the board getting hot or letting out smoke, an electrostatic zap, the USB cable being pulled on)? Also, could you post some pictures of how everything was set up, as well as some close-up pictures of both sides of the problematic board?

Brandon

[Vinnie]

Attached is the setup I’ve been working with:
Front:

Back (for wire routing reference):

And I’ll refer to the non-functional Tic Controller as T825 #1. I removed the wires for troubleshooting but they are setup just like T825 #2.
Front:

Back:

Power to the Tic Controller is as follows:
External Power supply 24V 6A limit -> Slip Ring -> Voltage Regulator 12V 3A (up to 5A) -> Tic Controller #1 and Tic Controller #2 (on the same line)
USB Interface to Tic Controller: COTS cable to Raspberry PI 4B with relay board hat
Tic to Stepper Motor: 4 wire Nema 17 Stepper Motor (black, green, red, blue) routed underneath the panel

Just to clarify, if you disconnect everything from the Tic, and just connect the USB to your computer, do you see any signs of life from the Tic (e,g, LEDs blinking, registering in the computer’s Device Manager)?

Correct. I tested different cables with both Tic Controllers #1 and #2. But only #1 seems to be having the problem. Tic#2 was working fine.

Did you notice anything suspicious when the Tic stopped responding (e.g. a burning smell, the board getting hot or letting out smoke, an electrostatic zap, the USB cable being pulled on)?
Blockquote

I haven’t. I was running the system on and off for about a couple hours but haven’t touched any of the circuits (had a ESD band on). Didn’t smell anything burning and the motors were cold to touch (typically get a luke warm).

Just some of my notes,

• Tic #1 and Tic #2 were connected to the same voltage source (parallel to the regulator). So initial guess was that the voltage regulator wasn’t the problem.
• USB ports on the Raspberry PI 4 weren’t damaged, was still able to connect devices to all ports and were working fine.
• Motor wasn’t moving when this anomaly occurred.

[BrandonM]

Thank you for all the additional information. Sorry for the delayed response. I do not see anything obviously concerning with your setup or any visual signs of damage on the board. Without any clear indication of what particular components are damaged, and with the Tic showing no signs of life, it is hard to determine what might have gone wrong. Did you ever disconnect the motor from the Tic while it was energized?

If you would like to try again with another Tic, please email us at support@pololu.com with your order information and a reference to this post and we should be able to help you out with a replacement.

Brandon