Multiple organ failure 🙁
Hi Everyone,
I’m looking for some assistance. I’ve a Mk2.5 upgraded to Mark 3 which I’ve been using happily since 2018. Whilst replacing the cover for the hotbed connector, the previous one having started to melt, I managed to Nick the wire to the bed thermistor which contacted VCC ( the positive connector to the heat bed) and shorted. Now the printer won’t power up. Or to be precise the LCD doesn’t show a display.
I’ve checked the fuses from the plug, the power supply and the three ones on the Rambo board and all have continuity. So it seems to me that the Rambo board might have failed, and or the thermistor has failed and or the hotbed heating element has failed. That’s in order of likelihood.
I’m fairly knowledgeable about electronics and have reasonable test equipment. Is there a detailed fault finding guide with data such as how to test the thermistor, the hot bed and a schematic for the Rambo board? Given the current lockdown and the fact that I was printing face masks I’d like to fix it quickly.
Thanks,
Steve
RE: Multiple organ failure 🙁
Hi again,
I’m getting a resistance reading of 110 k ohms from the Thermistor and 1 ohm from the MK52 hot bed.
regards,
Steve
RE: Multiple organ failure 🙁
I’ve found some useful information here
https://help.prusa3d.com/en/article/multimeter-usage_2117/
they don’t say which model hot bed they’ve measured the resistance of. I’m trusting my MK52 is ok with a 1 ohm resistance. Either way they don’t seem to have stock.
I’ve ordered a new Rambo board and, to be safe, a thermistor, from Prusa. I contemplated ordering both from EBay or Amazon UK but the lead time seems much better from Prusa.
I’ll let you know how it goes...