Hi guys. Please check my previous post for any background questions, I don’t have it in me to go over everything again.
Long story short, I was having issues with clogging that were being caused by my hotend not reaching the reported temp. After a few days of troubleshooting and diagnosing the motherboard and Klipper settings, I gave up and decided the motherboard was faulty (even though I could not perform any tests to determine in) and bought an SKR mini. I got that all set up, and the printer has been working flawlessly since then.
Until now.
Same exact problem; one print goes perfectly fine, next print, failing to extrude by the 4th layer. I removed the clog, restarted the print, now can’t even extrude the priming line. Fearing the worst, I disassemble the hotend, try hand feeding filament, and once again I am unable to push more than a few centimeters through before it gets clogged up. A probe thermometer reads ~160C while Klipper reports 200C.
What could possibly be happening here? The board is an aftermarket replacement from a completely different company, so I doubt it’s a recurring manufacturer defect, but I have no idea what else can be causing this.
At this point I’ve spent so much time and money trying to fix this printer that I could almost buy a new one, but at this point I’m not convinced even that would solve the problem.
I did not, but yesterday I put marlin on the stock board (the first one to start doing the temp thing), and it’s doing the same thing, so the pi isn’t the problem.
I also tested the printer’s power supply with my multimeter and it’s stable between 23.8v-24.2v.
My house electricity is a little dodgy, my lights flicker for a half second when a high draw appliance turns on (AC, refrigerator, etc), but nothing in the house has ever been damaged by it in the 5 years I’ve been here, so I don’t think it’s strong enough to kill multiple boards, especially since it’s after a PSU. I suppose moving forward I can run the printer off a surge protector (I was running straight from the outlet because I was testing power consumption a few months back and never switched it back).
Yeah, that’s the thing with electronics. Sometimes the damage is not visible but the component doesn’t behave as expected anymore. Timing can be off, more bit flip happens, all sorts of crazy stuff, including a resistor that is not up to spec or damaged ADC. Haunted it is.
So it is.
I’ve ordered a new board to come in tomorrow. Once installed I’ll run the printer exclusively off the surge protector, we’ll see if we can’t make this board last longer than a week 😉
I had the semi joking idea of designing a breakaway cable that would simply plug and unplug all of my printer peripherals into the motherboard at once. That way, when I break one every week, it’s a simple drop and plug process.
Definitely look at it, totally worth doing or pick yourself up one of the tool head pcbs, I can be heavy handed and having to redo wiring bundles every time I want to change something sucks. Molex connector will work really well if you don’t go the PCB route.
As for damaging the board just by running it, the btt boards are super resilient, I’ve totally whoopsied with my octopus pro and shorted a fan header with multimeter and cut a wire I forgot was live on another. I pulled the jumpers on those headers, rest of the board has 0 issue considering the abuse it had thrown at it. I’d be really surprised if slightly dodgy power would damage 2 unrelated boards in a super specific way and damage nothing else.
This is my thinking as well, but I’ve got zero other ideas.
I’ve already cut the wires on my heat cart and thermistors, so swapping those parts around is easy.
I’ve seen printers with a PCB on the hotend, but I’m not sure I understand what it is that the PCB does; is it simply a port hub between the main board and the hotend to make parts easier to swap out, or does it do any actual “thinking”? If it’s the former, I think I’ve more or less accomplished this with the connectors. If it’s that latter, I have no idea how I would go about configuring that to work with the SKR, but it would probably solve my problem by moving the “temp calculation” job off of the main board. It would at least tell me for certain if the board is what’s reporting the incorrect temp.
The PCB doesn’t do anything other than a compacted connector between components. Especially the surface mount component. Also, some devices can be more sensitive than others making it more prone to breaking during mishandling. If something on the pcb breaks (highly unlikely), then you can just solder using jumper wire (to some degree, high speed signals cannot be treated this way). However, if the component on the PCB is the one that breaks, then you can just replace that component with some careful solder works. But yes, sometimes replacing it will be easier than repairing
I use a version of Hartk’s Stealthburner PCB on my voron and cludged an afterburner tool head onto my franken mk3s. They’re both breakout PCBs, the stealthburner one to my knowledge is passthrough, afterburner one has a thermistor and led on it for chamber temps and a hotend activity led. Totally optional and what you’ve done already is probably the more frequent things I’d change anyhow. There are fancier tool head boards, they’re effectively their own MCUs afaik that communicate via canbus, with those ones you’re running very few wires, something I’m thinking about but haven’t done yet
For me, they reduced the amount of wiring I needed to run to the hotend and make it super easy to swap components, as I said, I’ve damaged things unintentionally before (I’ll say ADHD is contributing to that) so it’s really handy. Keeps the wiring neater as well, or at least gives you a place to manage them.