SB2209 not detected by Klipper | VORONDesign | Page 1

dapper cipher Feb 2, 2026, 3:23 AM

#

Hi Everyone,

I am buidling a Formbot Trident .I'm stumped on issues with the SB2209. Due to intermittent power failures on the print head, I replaced the can cable (West3d) and installed it Saturday. Klipper immediately reported not being able to see the toolhead. The printer was working for hours the day prior for testing. Since the cable replacement, Klipper has been unable to see the SB2209.

The heatsink fell off the SB2209. I don't know when. The printer hasn't done much other than homing and basic movements, but it's not clear how much heat that generates.

Troubleshooting completed

Swapped in the old cable. Confirmed same activity.
Referenced board pictures to be certain that the cable was plugged in correctly.
Confirmed that the Manta8p is still being detected by Klipper.
Confirmed the device is visible in DFU mode.
Attempted to reflash using Katapult. It appears to be successful, "Found rp2040 device on USB bus 2 address 10" (Esoterical's guide was the reference)
Confirmed that the device has no Katapult ID after the flash.
Performed basic troubleshooting from Esoterical's site including - Validating the CAN network bit rate and qlen, checking status of the CAN network, validating there is minimal to no traffic on the CAN network, commented references to the SB2209 mcu in my printer.cfg.
Updated the Manta8p Klipper firmware.
Updated Klipper packages.
Tried flashing the Manta from scratch. Manta seemed to flash successfully.
Confirmed the can network is up but there's minimal traffic on it.
Rebuilt Klipper OS.
Confirmed 120r jumper is installed

So, I have two theories - heat and electrical. I have to work on finding new heatsinks and a multimeter. Is this the right track? Is there other troubelshooting I should be doing?

#

📎 klippy-19.log

eternal wedge Feb 2, 2026, 4:04 AM

#

dapper cipher

Assuming you have the M8P 2.0 currently connected, the can bus pins are incorrect on the klipper firmware that you built and flashed on it.

#

I'm not sure this is the only issue as you seemed to indicate the can bus at one point was working, but you also say you've changed a bunch of things on it since then as well.

dapper cipher Feb 2, 2026, 5:00 AM

#

Thank you! I appreciate you pointing this out. I will check things and follow up.

dapper cipher Feb 2, 2026, 1:40 PM

#

I reflashed the Manta and see the same results. I didn't have time to troubleshoot much this morning, so please bare with me if something obvious was missed.

📎 klippy-24.log

eternal wedge Feb 3, 2026, 1:18 AM

#

dapper cipher I reflashed the Manta and see the same results. I didn't have time to troublesh...

The M8P looks better now. Can you run ip -d -s l l can0 and screenshot the output? Also some clean pictures of the M8P and SB2209 boards that show the CAN wiring would be helpful.

dapper cipher Feb 3, 2026, 1:36 PM

#

The requested screenshot is attached. The activity bytes sent and received are increasing now. I checked activity before posting. I will post the Manta and sb2209 photos from my phone. I'm assuming you're interested in the 120R resistor on the SB2209. I can potentially get that after work.

#

#

The green and yellow wires were swapped on my old can cable. Swapping them here didn’t seem to make a difference. I haven’t gotten a multimeter yet to measure the ohms though. The old cable doesn’t work either.

eternal wedge Feb 3, 2026, 2:32 PM

#

dapper cipher The green and yellow wires were swapped on my old can cable. Swapping them here...

I think I can see the 120R jumper on the sb2209, so if you confirm that it's on there, that's fine. I'm not sure what cable you're using, but on the BTT cable supplied with the sb2209, the green wire is low and the yellow wire is high. If that's the BTT cable, it's been modified a bit and I obviously can't see how those wires are connected at the toolhead end, but on the manta side, that connector has the wires flipped around with the green on the high side and yellow on the low side.

Try double checking the katapult flash on the sb2209... flash it again if you're unsure. After the flash, confirm that it's pulsing its status light to show that it's booted to katapult and check for its uuid on a can bus query.

A meter would be helpful here to check the wiring.

dapper cipher Feb 3, 2026, 2:57 PM

#

Thank you for your responses. The 120R is on the Manta. I checked previously on the SB2209, but have to dismantle it to validate. I could do that later if we feel that necessary.

The installed cable is the West3d Can cable. It swapped the wire colors. I've tried swapping the wires without change in experience, but will aim to get a multimeter this week to validate the measurements.

Attached are the settings used to flash the sb2209 with Katapault. The red LED on the SB2209 pulses immediately after being plugged in. Attached is the screenshot of the last Katapult config flashed to the device and the output of the UUID command.

eternal wedge Feb 3, 2026, 3:09 PM

#

dapper cipher Thank you for your responses. The 120R is on the Manta. I checked previously o...

The katapult settings for the sb2209 look fine. I don't think you need to disaasemble anything to check for that jumper. You should just be able to look under that trim piece at an angle to confirm. A meter will be able to confirm that it's there as well.

dapper cipher Feb 3, 2026, 3:27 PM

#

Thank you. Will report back once I have the multimeter

dapper cipher Feb 4, 2026, 2:39 AM

#

With the Manta unplugged and all jumpers in place, Can L measured 120 ohms. With the cable connected, all jumpers connected, and measuring the from Can L pin on the underside of the Manta I get about .6. This feels like I did something wrong. I didn’t see how to measure Can H from the sb2209.

The guidance that states “With everything connected, measure resistance between CAN_L and CAN_H. You should read 60 Ohms (2x 120 Ohm in parallel = 60 Ohms). If you get 120 Ohm, then there might be a break in the wire or you forgot to set the jumper”. I understood that to mean measure Can L on one end and Can H on the other while cables and jumper are plugged in. No power. That result was essentially zero (.003 or so)

eternal wedge Feb 4, 2026, 3:29 AM

#

dapper cipher With the Manta unplugged and all jumpers in place, Can L measured 120 ohms. Wit...

Right, so what you want to measure is the resistance with one probe on L and one probe on H. With the power off and everything connected, it should read ~60 ohms as the guide states. If you look at the sb2209, the bent L and H leads going from the connector into the board are exposed and that would be a good spot to measure.

Even if you probed L on one board and H on the other, that's effectively the same thing and still should give you ~60 ohms. The near zero reading you got doing this suggests you are probing the two ends of the same wire, which usually means that the L and H are flipped at one end.

#

Consider this diagram of a CAN layout. The nodes are your boards and the dots coming from them are basically where you placing your probes.

dapper cipher Feb 4, 2026, 1:31 PM

#

Thank you. That explanation helps. It sounds like I was on the right track. I’ll try swapping the wiring to the board and test again.

dapper cipher Feb 4, 2026, 11:31 PM

#

Redid the tests and understand better now. 117 ohms on both can l and h with one end disconnected. With the 120r jumpers installed and both ends plugged results in about 60ohms.

eternal wedge Feb 5, 2026, 2:15 PM

#

dapper cipher Redid the tests and understand better now. 117 ohms on both can l and h with on...

If you haven't run into this already, this is a good troubleshooting guide: https://canbus.esoterical.online/troubleshooting/no_uuid.html It has some more tests you can use to verify the wiring is correct.

It looks to me that the Pi and Manta are setup correctly. Confirm that the wiring is right and you should be able see the sb2209 returning a uuid.

dapper cipher Feb 5, 2026, 2:37 PM

#

Thank you. I think my cabling is correct. I was measuring based on the labels on the boards and test both wires for each pin so the wiring should be in the right spot. Also my old cable has the same problem and it worked fine (expect for the power loss during specific movements) until the general loss of communication started. Assuming the wiring is correct, do we assume there’s something wrong with one of the boards? I have another Manta that could be used for testing and can aim to test that sometime this weekend.

At this point I have to admit that I’m getting frustrated with BTT products (or is my frustration misplaced and this is how can goes?). Regardless, if this is a bad Manta or SB2209 that would be the third or fourth BTT part (Manta, can cable, stepper driver) to have issues in this printer build. I’m debating moving to another vendor for this hardware and whether usb is worth considering over can. If that is less likely to produce issues I’m open to this.

eternal wedge Feb 5, 2026, 5:48 PM

#

dapper cipher Thank you. I think my cabling is correct. I was measuring based on the labels ...

Checking things with another board would certainly be helpful. It's often difficult to tease out the cause of the problem when you need all of these things to work together in the first place.

I personally have not had issues with BTT products. I have one octopus variant or another in all of my big printers and most all of my toolhead boards are BTT, so I may be biased. I just haven't had any real problems with them.

Mantas are also very popular among Voron builders for the 2-in-1 feature that they offer, so I wouldn't say you should give up on them. Just make sure they're powered off when you work on them and check everything 5 times before you power up.

dapper cipher Feb 5, 2026, 5:54 PM

#

Thank you for input. I have seen a handful of posts with people discussing multiple board failures so I’m glad to hear that’s at least somewhat siloed.

I’ll test the other Manta at some point in the next few days. It measures the same with a multimeter so at least that’s promising.

dapper cipher Feb 6, 2026, 12:48 AM

#

The old manta isn’t even producing an mcu value for itself and won’t boot into DFU mode.

At this point, I think I’m going to take a break from troubleshooting and figure out what my next action should be.

Thanks for your help. I truly appreciate the guidance.

dapper cipher Mar 1, 2026, 1:49 AM

#

Just wanted to stop in with an update and another thank you to Dormouse. A week or two ago, I bought a Nitehawk 36 and moved towards the A4T toolhead. Everything got installed today and the NItehawk board worked fine out of the box. No issues with the board or peripherals (though the fan wiring had to be swapped). There's still a lot to do, but the board seems to be detected properly now.

#SB2209 not detected by Klipper