Topics created by ReXT3D

Just a quick follow-up that can perhaps help someone else...

I ended-up purchasing a Crydom DC100D40, primarily because I was able to get it quickly and with free shipping, as opposed to the Auber relay that would unfortunately take a while to arrive and was very expensive to ship to my location.

I am now able to run up to 1kHz PWM frequency on the bed heater, although all light flicker disappears just above 100 Hz which is where I keep it. As another HUGE bonus, I am thrilled to have eliminated a potential fire hazard of the stock SSR.

The printer shipped with a DELIXI CDG1-1DD/40A SSR that was installed on two spacer posts with no heat sink of any kind. This SSR was running so hot in use that it was impossible to touch. For kicks, I measured the voltage drop on the SSR when it was on and my jaw dropped even more than the voltage when the multimeter registered 1.65V! This is equivalent to approximately 0.1 Ohm internal resistance, resulting in 27W of power being dissipated by the SSR while driving a 400W load. Unbelievable!

The Crydom DC100D40 under identical conditions measures 0.084 V drop, which is equivalent to just over 0.005 Ohm and 1.4W of power being dissipated. I mounted the Crydom on a small heat sink, per data sheet requirements, which in retrospect was totally unnecessary. The SSR stays cool to touch even under extended full load operation. Beautiful!

@dc42 are you saying the Mini has protection to avoid driver blowout as shown in magic smoke ? (That's M84 during a very fast linear move blowing out the drivers)

PS: this is neither RRF nor a duet board.

Quick update: after many prints and countless hours of me trying to purposefully trigger BL Touch misbehaviour, I can confirm that everything has been working perfectly.

In the end I did four separate things:

Routed the heater and stepper wiring in one bundle (high current & noise) and the BL Touch, fans, thermistor and stop switches in a second bundle, both spaced at least 2 inches apart. Added a ground reference wire between the main 24V printer supply and the dedicated MeanWell Raspberry Pi 5V supply that I use. The original setup worked flawlessly with the Creality Atmega board for almost a year, but I suspect that everything became more noisy with the high performance Duet and referencing the grounds through the USB cables just seems wrong. Even though, everyone who is using Klipper and an external Raspberry Pi power supply does exactly that. I disabled the internal pull-up resistor as discussed. I decided to retain the 33 uF capacitor near the BL Touch. I feel that it will provide a good reservoir for the initial inrush current associated with BL Touch pin movements.

@ReXT3D What settings did you end up using for Klipper? Did you set the sense resistor value to 0.076, or did you have to configure vsense somehow? I'm having some overheating issues with the example klipper config, even with the motor current set quite low.

@phaedrux said in New Duet 3 Mini 5+ external drivers header misaligned:

I don't think it would pose a long term issue, however that is not up to our standards and we will gladly issue a replacement to alleviate your concerns. Please contact your vendor and initiate a warranty exchange. Include a link to this thread as authorization. Sorry for the inconvenience.

Thank you very much. I am in Canada. I would not be normally concerned about this in any consumer electronics, but I have seen and measured how hot the TMC drivers normally run and over time I think it could be a potential reliability issue (I'm an engineer)...

Oh, and no need to apologise, I know quite well this is an imperfect world!