Duex5 5v Output is 2.8v

Design

Hi, we purchased a Modix big 60 with a Duet2 and Duex5. We were trying to diagnose an issue with the BL Touch which led us to test the 5v pins on the pwm inputs. I'm only reading 2.8-2.9v between the 5v and ground pins on each pwm input. The 3.3v, 12v, and 24v readings are all accurate. Is there a jumper or configuration variable that needs to be changed, or is the 5v regulator defective/dead? Any help is appreciated.

T3P3Tony

@Design please measure 5V between these two points:

(https://docs.duet3d.com/Duet3D_hardware/Duet_2_family/Duet_2_WiFi_Ethernet_Hardware_Overview#physical-connections)

Also for the BL touch, I assume you are following these instructions:
https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_connecting#wiring-the-bltouch

Design

@T3P3Tony Those pins measure 4.93v. The BL touch came wired from the manufacturer along with the firmware. Looking at the provided link, everything appears to be wired correctly. Duet2 hardware version is 1.05.

Phaedrux

Have you been in touch with Modix support yet?

Design

@Phaedrux I contacted them but have not heard anything back.

Design

@Phaedrux Modix support has asked me to reply here that the 5V readings on the Duex expansion board are all in the 2.8V range. They would like your input here to see if anything was missed before they issue a warranty replacement.

T3P3Tony

@Design please send a clear image of that area of the board (PWM pins), voltage select jumper etc.

dc42

@Design did you measure that voltage with nothing connected to the Duet except VIN and power?

Is there also a DueX expansion board in the machine, and if so, have you disconnected the ribbon cable?

It's possible that the 5V regulator is faulty, but it's also possible that something connected to the Duet is drawing excessive power from the 5V rail.

elmoret

@dc42 if the rail was being pulled down (or the regulator was faulty), he wouldn’t have 4.93v would he?

Maybe measured through a switched ground and saw leakage through an off mosfet?

Design

@dc42 The 4.93V is measured on the Duet2. The 2.8-2.9V is measured on the Duex5 when connected to power and the Duet2.

@T3P3Tony I will post a picture when I have the opportunity to take one.

@elmoret I measured pins "5V AUX" and "GND" on PWM5 in this pinout diagram. I also measured "+5V" and "GND" on the GPIO and I2C header of the Duex5 from this pinout diagram. Both of these produced voltages in the 2.8-2.9V range.

https://docs.duet3d.com/duet_boards/duet_2_expansion/duex_wiring_v0.11_d1.0.png

dc42

@Design said in Duex5 5v Output is 2.8v:

The 4.93V is measured on the Duet2. The 2.8-2.9V is measured on the Duex5 when connected to power and the Duet2.

Sounds like a faulty ribbon cable then, or possibly a bad 5V or ground soldered joint on the expansion header of the Duet or the DueX.

Design

@dc42 How would you like me going about checking that?

Phaedrux

Can you test the resistance of the ribbon cable conductors with a multimeter?
Can you provide a photo of the expansion header pins and solder joints?

Design

@Phaedrux Okay, looks like the ribbon cable may have been "part" of the issue. I noticed that the tops of the connectors on the ribbon cables did not seem seated fully. I removed the ribbon cable, re-seated the top piece, and re-inserted the ribbon cable. I am now receiving 5v on the duex.

The BL-Touch is still not working properly. It runs the self test on bootup and passes, stays lit red, but will not deploy/retract, or trigger. I'm using the default modix files, but I think it may be best if I start a new topic on this issue.