PSU Shuts off

I switched from a melzi to my old ramps 1.4v because my melzi quit working. I have a heatbed and 1 hotend. I think my psu is under too much load, once I click print everything shuts off. I quadruple checked my wiring, no shorts. I have a load on the 5v line aswell. Thinking my PSU crapped out. Its a 500w ATX

Sound like a current protection kicking in. I always used ATX power supplies as a lab supply because I could short them out without releasing the magic blue smoke. put a voltmeter on the 12v rail and check the voltage. Make sure that it doesnt drop below 12. Then try hitting print without the heated bed connected. If it starts, then try a better power supply, or if it is an aged power supply, then take it apart and look for bulging capacitors: [www.markdigital.com] If you can find any then it can be repaired if you are comfortable soldering.

Its less than 6 months old but I guess it did go. I get 12v but aload more than 100w seems to kill it. I use atx for the same reason you do, no blue smoke. I found a 400w lying around and used that, it seems to work now. Its a Arum Gold 500w psu, what would make it cut out underload othere then the caps? Would like to try to fix it.

How much load do you have on the 5V output? When you increase the load on the 12V output, the voltage of the 5V output will increase on most ATX PSUs. This may cause overvoltage on the 5V rail if it is loaded too lightly, causing the PSU to trip.

Edited 1 time(s). Last edit at 02/22/2015 01:33PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I had a fan and a Disc drive on the 5v rail

Quote
twigg1012
I had a fan and a Disc drive on the 5v rail

The fan is far too light a load. The disc drive will also be a very low load unless the motor is actually spinning. Try a heavier load on the 5V rail. A 12V 21W auto brake light bulb would be a good start.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Find a 10w 10ohm power resistor and heatsink it to a large metal surface. As for bad capacitors, if there are any, they just need to be desoldered and replaced with new ones. This is how to get free computer monitors on craigslist, they have the same fault.