Voron 2.4 Formbot kit new build: the infamous "unable to read tmc uart extruder' IFCNT" issue

[past zodiac]

Hi all,
So here it goes: I’m finishing the build of a Voron 2.4R2 Pro, using a Formbot kit purchased last January. The basic setup is based on a BTT Manta M8p v2.0 board, with a CB1 module, and a stealthburner kit that includes an EBB SB2209 + EBB0000 boards, so I'm using a CAN bus and an umbilical connection.

Mechanical assembly is finished, software installation was completed, including flashing . Mainsail works correctly from a PC’s browser, HDMI5 display working correctly also.  I have  tested and calibrated movement in the three axes, heated bed works correctly, hot end works as expected.

The only thing that does not work is the extruder motor. I receive the message:

Unable to read tmc uart ‘extruder’ register IFCNT

Investigating:

1. The CAN bus works, since I have full control of fans, stealth burner LEDs, heater and thermistor. X-axis endstop also works as expected.
2. The EBB 2209 board receives power, confirmed by all attached devices, except for the extruder motor.
3. The fuse behind the board has been tested and is not broken
4. Testing has been done both with and without the EBB0000 board, to inspect for shorts or other problems
5. GPIO pin configurations in printer.cfg have been checked based on Formbot's sample file, and I checked every gpio ID using BTT's documentation for the SB2209.
6. A sample printer.cfg from https://github.com/bigtreetech/EBB/blob/master/EBB SB2209 CAN (RP2040)/sample-bigtreetech-ebb-sb-rp2040-canbus-v1.0.cfg shows a line “dir_pin: !EBBCan:gpio19”, while Formbot’s sample config has “dir_pin: EBBCan:gpio19”. Both have been tested, no effect
7. printer.cfg in Klipper has been modified and tested many times, including the use of uart_address (values 0, 1, 2 or 3, no effect)

The motor included in the kit is a Moons NEMA 14 Pancake with a 10 tooth gear. Mechanical assembly of the Stealthburner was completely successful, with calibration steps performed according to Voron’s SB manual.

What can I be missing??

[rain chasm]

Can we get a klippy log?

[past zodiac]

Sure: https://www.dropbox.com/scl/fi/ysq3mohsjd5fxrum0gwxn/klippy-3.log?rlkey=0evjz4nveiwnhbags4vnee4eq&dl=0

[rain chasm]

Sorry, can you just post it to the channel? I don’t feel like battling Dropbox

(Plus button left of the typing box)

[past zodiac]

The log is 3.2MB, I can send if uncompressed if it's acceptable. Some more info:
DUMP_TMC STEPPER=extruder returns
17:51:48 Unable to read tmc uart 'extruder' register GCONF
17:51:48 ========== Queried registers ==========
17:51:48 SGTHRS: 00000000
17:51:48 TPOWERDOWN: 00000014 tpowerdown=20
17:51:48 COOLCONF: 00000000
17:51:48 TCOOLTHRS: 00000000
17:51:48 TPWMTHRS: 000fffff tpwmthrs=1048575
17:51:48 IHOLD_IRUN: 00081414 ihold=20 irun=20 iholddelay=8
17:51:48 SLAVECONF: 00000200 senddelay=2
17:51:48 ========== Write-only registers ==========
17:51:48 DUMP_TMC STEPPER=extruder

[formal swift]

Uncompresssed is fine. Many of us won’t open zips for security reasons.

[past zodiac]

Here you go. Sorry for the confusion.

[rain chasm]

Because this server has lots of boosts, file size is generally not a big concern here

Anyhow…

Config seems more-or-less in order

You mention having successfully calibrated the stealthburner

How did you manage that, given the error?

[past zodiac]

Oh, I meant the mechanical fine-tuning from the SB assembly guide, gear meshing, tension, anti-squishing.

I ran PROBE_ACCURACY, PID_CALIBRATE HEATER for the bed and the extruder, and all other tests in Voron's startup guide, up to the point of calibrating the extruder itself ("finish line" in the guide).

[rain chasm]

Oh oh. Gotcha

Is the behavior any different if you don’t have the motor plugged in?

[past zodiac]

No, the DUMP_TMC returns exactly the same

[rain chasm]

Then my suspicion is that it’s just a bad board

You’ll probably have to hit up formbot for a replacement

[past zodiac]

The feeling is that no power is reaching the motor. But the SB2209 is powered -- everything else works, and I tested with a multimeter. The fuse that protects the motor connection is whole... I was afraid that the board might be the culprit.

Well, it takes 3 weeks for anything to reach Brazil from China... Voron on hold for a while 🙂

Thanks for the outlook. I'll take the board out anyway, to see if there is anything obvious -- a short, bad solder, IDK.