Automatic Calibration Crashes/Freezes/Broken

[littlecatlabs]

So, I've been having a lot of fun with my new HE280 hot end assembly lately - apparently too much fun. I have been tinkering with it for the last couple days, experimenting with swapping in the heater block assembly from an e3D Volcano, and now the calibration routine is going crazy and I'm worried I may have damaged my hot end PCB. The auto-calibration commands were previously working well for me, but now the script crashes every time. It's consistent: it starts the G29 sequence correctly, homing at the top, dropping down the center as it should, stopping about 20mm above the plate, and scooting over to the base of the X column. That's when it breaks. Instead of smoothly dropping into the tapping/probing movement, the carriage abruptly drops about a centimeter, and the firmware blows up. The motors lock, so do the heaters if they happen to be on - - the UI freezes, the LCD becomes partially populated with ominous blocks of white pixels, and the COM port goes silent. Sometimes, the carriage pulls out of its first freeze after a few seconds, and, without ever tapping the bed, drags itself over to the base of the Y column and then freezes again, this time for good. Also, the thermistor seems to be working properly - most of the time - except that when it's heating up the temp reading sometimes jumps randomly upward by as much as 100 degrees and then abruptly drops back down again.

My printer was once a Rostock Max v1 and is still running its original RAMBO board from 2013. All of the moving parts have been upgraded to v3 hardware except the motors. The power supply is a 12v 600W ATX unit I picked up a while back. I am using the original 100K thermistor that came with the HE280, and the 12v heater cartridge/block assembly from an e3D Volcano. Firmware is up-to-date as of yesterday. Since I have had the HE280 I have always told the firmware that I'm a Rostock Max v2 (even though I'm technically a v1, which isn't listed), and before now that did not appear to be a problem. I did try erasing and re-flashing the firmware but it didn't help. None of the connector pins are obviously broken or loose. That said, I haven't disassembled the cable connectors and redone all the pins - sounds tedious - but some users apparently swear by it, so please let me know if you think bad pins are the likely source of the problem.

If I borked my board, I'll buy a new one. But I don't really want to shell out and wait unless I'm pretty sure that's what's wrong, because it would be annoying to swap it in a week from now and then see exactly the same behavior. Please let me know if you have encountered anything similar or have any advice. Thank you!

[Dale Eason]

That kind of behavior is more likely caused by loose wiring or pins that gets triggered by the movement of the carriage to the side.
Dale