ATX PSU shuts off while temperature is stable

Hello,

I am currently using a RAMPS 1.4 (with Marlin 1.1.8) with an ATX PSU. The board is unmodified (12V input). While the extruder and the heatbed heat up (constant voltage on both outputs) everything works find. Once the final temperature is reached, the heating cartridge is quickly turned off and on again to keep the temperature stable (couple of Hz). The 12V output of the PSU seems to be stable during the whole process. Then after a random (but not to long) time the PSU shuts off. I already tried using a balancing load on the 5V rail. The fast switching of the heating cartridge seems to be the problem. Is there any way to lower the switching frequency or any other way to solve my problem? I already tried another PSU and it works flawlessly (but I need it for my PC). Both 12V rails of the failing PSU supply 18A so this should not be the problem.

When I ran a Seasonic ATX, I found that the bed using PID severely messed with the short circuit protection in the power supply. I solved it by using bang-bang on the bed (continued to use PID on the hot-end), and it no longer had any problems.

Edited 1 time(s). Last edit at 06/16/2018 09:06PM by Diggrr.

I just tried that, but it did not help. I am completely out of ideas.

Quote
Knicklicht
I already tried another PSU and it works flawlessly (but I need it for my PC). Both 12V rails of the failing PSU supply 18A so this should not be the problem.

If you are having problems with one of two Atx power supplies. Then it would appear that the failing Atx supply is not capable of supping power but what voltage level is failing.

Quote
Knicklicht
I already tried using a balancing load on the 5V rail.

Is the 5V or the 12V supply failing.

Could you explain more about how you have the 3D Printer wired to this Atx supply. And could you post the specs of the two Atx supplies.
Let's determine what is causing the supply to fail.

Is it the hot-end heater, the Bed Heater, temperature variance shutdown or is the supply simply not capable of supping the continuous power requirements.
Try to print PLA with the hotbed off? This will determine if the Atx supply can handle the rest of 3D Printer components.

Edited 3 time(s). Last edit at 06/17/2018 02:28PM by Roberts_Clif.