Topic: Bed heater seems to have failed
I asked about this in the IRC channel and also sent solidoodle support an email, but I'm also posting here in case anyone else has had the problem or has some advice.
My SD3 is barely more than a month old and, given the amount of delays while I went through the "necessary" mods to get successful prints, I have really only just started to be able to print on it. In fact, I haven't even managed to change filament and successfully print in a second color yet.
Last night, I came home from work and wanted to do a print that would take about four hours. Not wanting to leave the SD3 running while I slept, I plugged it in, set up the enclosure and glass bed, started up Repetier, connected, and turned on the extruder and bed heater. Since the latter takes at least 20 minutes, I then went out to take the dog for her evening walk, expecting to return to find the bed temp in the high 70s or low 80s.
When I got back, I found the extruder was at full temperature, but the bed was still in the 30s. I checked the Temperature Curve screen in Repetier and found that it had hit a peak of about 68 and then started to trail off. I put my hand over it and it felt like the reading was right -- it was too hot to hold my hand on, but not so hot it burned, just like you'd expect for a temp in the 30s.
I tried shutting off the bed heater and turning it back on, and doing the same with the whole Solidoodle as well as with my computer, just to rule those things out. I traced the wires from the bed and made sure they were all seated and had no obvious rips or other problems. (I assume the red pair is the actual heat, and the black pair is the thermistor?) On advice from someone in the IRC channel I checked the voltage from the power supply and it was solid 12.27VDC. I visually inspected where the red and black wires go into the area under the print bed, above the insulation (had to peel some of that back temporarily) and saw no clear problems. I confirmed that everything else seems to work -- the extruder reaches temperature and filament oozes out, the bed and extruder both move, the lights are on.
But meanwhile the temperature kept sliding back down towards room temperature. After a couple of hours I just unplugged it all and put it aside, having run out of things to check.
If anyone has suggestions for something I can test to troubleshoot where the problem is, or maybe fix it, I'm all ears.
I'm also interested in hearing how hard it would be to replace the heating element. As this is my first 3D printer, I have had a hard time with some of the directions I've gotten, because often they assume knowledge I don't have (such as terms and acronyms I don't know, or calibrations like "not too tight" where I don't know how tight is too tight), but whenever I can get past the lack of knowledge specific to these kinds of devices and get some clearer explanations, I've got the aptitude to do what needs doing. I'm not too solid with a soldering iron (I can do it, not well enough to trust my skills on the crowded motherboard of a finicky, $800 device, but well enough to handle most simpler and less fragile things), but I can certainly take things apart and put them back together, given instructions and/or diagrams. But I'm a bit too timid to start trying to disassemble stuff without those directions.
I'm hoping this will turn out to be as simple as putting in one of these:
(That says it's for the SD2 but I wouldn't be surprised if they use the same one for the SD3. Certainly not going to order one until I'm sure of that, and that that's what it needs, and that solidoodle isn't just going to send me one on warranty anyway, and that I'd know what to do with it if I got it.)
Sorry to need as much hand-holding as I do.
