ATX Power Supply

Hello all,

My 650W Corsair ATX PSU kicked the bucket a few weeks back, and I decided to get another ATX power supply (my previous experience with an LED power supply was pretty bad; it lasted for a few days before it died). I went for a 500W semi-modular supply from Rosewill (Glacier 500M). Did I choose well or poorly?

Currently, my cave-man wiring scheme was to simply connect four cables from the PCIe cable to my printer. With my previous supply, this worked mostly fine. However, this does not work for my new PSU. I simply cannot get the heated bed to temperature! I was having an issue with my previous supply when heating up the heated bed where at around 80C it would no longer supply power, but this was after using the supply for several years. Since it is happening with my new PSU as well (including unreliable motor engagement -- sometimes it will move when I tell it to, most of the time it does not) I'm thinking that maybe the problem was with my wiring scheme. After all, I'm trying to tell the supply to give me nearly its full power output on part of a PCIe connection.

I am considering using 2 of the 4-pin 12V cables and wiring them together such that each power input on the printer has two cables for 12V and gnd. Would this help? Any other advice would be appreciated.

Sigh..... lesson one
At the currents people try to draw with heated beds over a small number of wires (in your case 4) you get stupidly high levels of voltage drop. If you going to do it at least use every single 12V and Ground wire to supply power.
Power supplies will supply all the power they can up to the rating providing the cabling is up to it, obviously yours isn't if your bed stops heating..... it's voltage DROP on your cables!

Lesson 2
Crap LED supplies are that just crap... BUT even the cheap 350W MeanWell clone supplies are excellent these days.... My 24V Delta got a donor 350W MeanWell clone from the xmas light setup that is a few years old now and has already had a hard life.

Personally as you may have surmised I think you choose poorly... at least fix your wiring.

Thank you for the response. I had been fretting about voltage drop or a disconnect between the RAMPs board and heated bed (I had convinced myself that the issue was resolved if the the Y-carriage was in a certain position, so I figured that wire was not in a good state), so I did replace that wire with a wire of a lower gauge (radius is inversely proportional to impedance), but of slightly longer length. I did some rough calculations and felt that it would be better than what I had before, but like an idiot I neglected the critical wires feeding the entire printer.

I'll address the main power wiring situation and see if that improves things. I'm optimistic it will. But if it doesn't, thank you very much for the power supply suggestion.

My three cheap LED supplies have served me well, with no failures. But from what I read, the infant mortality rate of these PSUS is higher than it should be for kit that is well designed and manufactured. The Meanwell PSUs may have a lower failure rate. Some of them at least have PFC, which means they must use a different design because the cheap ones don't.

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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 am doing the same thing only I have at corsair 430 watt that wasn't modular. I am just using four of the wires from the PCIE connector and I am printing right now with the hotend at 245 and the bed at 100. I have only had it setup for a few months but I don't feel I am taxing anything because the fan on the psu doesn't kick into high, the wires are at room temp, and it doesn't take any longer to heat up than it did with the LED strip psu.

I would guess your problem is something else since you were operating correctly with the old psu then you get a different psu and are seeing the same issue.

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Newbie with Folgertech 2020 i3.

aussiephil, I reduced the length of my original wires and supplied 6 wires to 11A connection and 4 wires to 5A connection, and everything works great so far, except for one annoying detail.

My heated bed acts a little funny. If I go right for 90-100C, it tends to crap out around 82C and not take any power for a while (<60C typically). If I have it reach 80C through a few increments of temperature (up 10C and let it hold for a few minutes), though, I can have it go to 100C with fewer problems. I have considered shortening the wire to the heated bed, but that was why I had to replace the wire the first time (limited range of Y-carriage because I had it so short, and even then I had this funky problem). Any thoughts on this? I thought maybe this was a problem from my old ATX PSU, but seeing it on the new one too makes me wonder what could be wrong.

Quote
KD0SKH
aussiephil, I reduced the length of my original wires and supplied 6 wires to 11A connection and 4 wires to 5A connection, and everything works great so far, except for one annoying detail.

My heated bed acts a little funny. If I go right for 90-100C, it tends to crap out around 82C and not take any power for a while (<60C typically). If I have it reach 80C through a few increments of temperature (up 10C and let it hold for a few minutes), though, I can have it go to 100C with fewer problems. I have considered shortening the wire to the heated bed, but that was why I had to replace the wire the first time (limited range of Y-carriage because I had it so short, and even then I had this funky problem). Any thoughts on this? I thought maybe this was a problem from my old ATX PSU, but seeing it on the new one too makes me wonder what could be wrong.

I'm a Duet user so this is a bit of a guess but it sounds like a heater timeout issue/setting on your controller as the bed is not heating fast enough.... sounds like you have enough power to reach 100c (just) but not before you get one timeout. Don't shorten the heat bed wire, increase the wire thickness. I would suggest a minimum of 16AWG from your controller to the bed and even 14AWG, this will allow respectable (needed) lengths with little voltage drop. you should be able to buy the wire from your local hardware store or find you local christmas light nut and see if they have some lying around