<p>I had my 3D printer powered by dual 24 V PSUs wired in parallel and my heatbed was wired into the main using a SSR to help power it. I replaced the two PSUs with a single Corsair 750 W ATX. My printer runs smoother and there's much less wiring clutter to deal with but now no matter what the heatbed will not heat up.</p>
<p>The main connection of the ATX I purchased is an 8 pin connection so I tried using all 4 wires to power my printer and it didn't make a difference, I tried using the SSR again using 2 connections from the ATX leaving the other 2 to run the motherboard but that didn't work either. I even tried MOSFET and that also failed. I don't see why the Heatbed no longer heats up yet the thermistor is more accurate and working properly since my switch to the ATX, do I need to go up to a 1000 W ATX instead? I can't imagine what more I could do.</p>
<p><img src="https://i.stack.imgur.com/hJMYN.jpg" alt="Schematic of PSU, bed, control board and SSR" /></p>

[{'answer_id': 14450, 'author': 'DoxyLover', 'author_id': 20164, 'author_profile': 'https://3dprinting.stackexchange.com/users/20164', 'pm_score': 1, 'selected': False, 'text': '<p>You indicated that you were using 24 volts, implying you have a 24 volt bed. ATX power supplies do not have 24 volt outputs. The highest is 12 volts which would heat up the bed, but not fast or probably to full temperature.</p>\n'}, {'answer_id': 14452, 'author': 'user77232', 'author_id': 12857, 'author_profile': 'https://3dprinting.stackexchange.com/users/12857', 'pm_score': 0, 'selected': False, 'text': "<p>voltage = current x resistance</p>\n<p>An ATX PSU is designed to only allow approximately 16 amps per pair of YELLOW and BLACK wires. The yellow is 12\xa0V and the black is GND. If your bed were rated at 24\xa0V then its resistance would be higher than that of the 12\xa0V bed. The best solution for you would be to get a 12\xa0V heated bed, as opposed to using a boost converter. Reason being is that you would need to get a boost converter that can tolerate over 200\xa0W of power! It's just cheaper to replace the bed.</p>\n<p>Finally, you need to consider the heat bed, the extruders and the steper motor's power needs before you purchase a PSU. If you had a multimeter with a current measurement, then you could accurately determine how much power each one uses and then purchase to size.\nBased on your bed size (600\xa0mm) I think that 500\xa0W should be enough.</p>\n"}]
['https://3dprinting.stackexchange.com/questions/14443', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/9861/']