ATX and LED psu dillema

I'm running a 12v 200W silicone heater. Initially, it was hooked up to a 25A LED China PSU. When the bed temp was 75C, I had no problem running my hotend at 260C (temp for my specific PETG). The PETG was sticking too well to the Kapton causing it to bubble, so I bought a glas bed and uaing some hairspray. I raised the temp to 85 because glass is about 10C cooler than the Kapton. I have a problem with my PsU maintaining 260C hotend. So I bought an ATX PSU at 35A to the 12v rails. Problem solved with regard to maintaining temp. However, the heat bed is wired to the CPU clip via a 4 pin female to 8 pin male connector. The 8 pin wires were soldered together. I followed the description on the wiki that didn't require ruining the PSU.

My proble, now is the CPU extension wire started to get to hot and melt. So that is not going to work apparently. I wanted an ATX supply npbecause they are built to a better standard and quieter. I though maybe using all 8 pins of the CPU would help. But I am not so sure. Is this fixable and workable?

My other option is to change to a PCB heat bed, and r buy a 33A LED supply. The silicone bed draws a shit ton of power apparently.

Any help would be appreciated on a resolution.

PC Power supplies vary. They can have 1 rail, 2 rails.. Each rail provides a part of the total amperage / watts of the output.
There is nothing to say they are spit equally at 50%. There is probably a better way of saying what I am trying to say.

The only way is to look inside the PSU to see where all the wires go, maybe there is 2 rails and when you tie them together can cause a problem.
Maybe 1 rail is all there is and the wires are too thin.

Good rule of thumb is the heavier the power supply, the better the quality.

Your PSU says 35A , that is everything added together

China PSU's, get the one's with a built in fan. For me, the one's without fans seem to give out after a couple of weeks.

It's 35A on one rail for 12V. Total output is 500W. It's a quality PSU, so I don't know why it is frying my wires. Perhaps because they are 18 gauge, but there are 4 tied together for each positive and negative. I don't know if I want to mess with a new heat bed, so perhaps the China PSU is my only options as I can put 14 gauge wire on it, which just gets warm and doesn't melt.

Hey dude,

I also trust a good ATX PSU way more then a Chinese hung low brand.

My Corsair VS450 has one rail with 34 amps, it had 12 12v cables, the 6 pin PCI-E had some thicker cables.
I wanted to make a nice adapter cable, but there are so many ATX revisions that it remained unclear how much a connector could handle.
And then you have 4 pin connectors with normal pins, gold pins that could handle more etc, in the end I cut of every thing I did not needed.
Made 2 groups with the 12v wires 8 for the heat bed and 4 for the hotend and electronics and soldered 2 cables on them.
I wanted to solder them directly to the PCB but I could not get it hot enough, lead free solder pfff :-)

It works very good,

Take care.

I didn't want to destroy the PSU, so I used this method [reprap.org] at the bottom. In theory it should work the same a cutting up a supply. I'm not sure if only using 4 pins of the CPU connector with 8 writes is causing the overload and the writes to melt. I suppose I could try using the 8 pins and see if it makes a difference. Or perhaps take all of the 12v writes than remain for use in the heat bed.

Quote
voyager
Hey dude,

I also trust a good ATX PSU way more then a Chinese hung low brand.

My Corsair VS450 has one rail with 34 amps, it had 12 12v cables, the 6 pin PCI-E had some thicker cables.
I wanted to make a nice adapter cable, but there are so many ATX revisions that it remained unclear how much a connector could handle.
And then you have 4 pin connectors with normal pins, gold pins that could handle more etc, in the end I cut of every thing I did not needed.
Made 2 groups with the 12v wires 8 for the heat bed and 4 for the hotend and electronics and soldered 2 cables on them.
I wanted to solder them directly to the PCB but I could not get it hot enough, lead free solder pfff :-)

It works very good,

Take care.


[attachment 77610 20160506_011754.jpg]

I used a Corsair CX430 and it works great. I also used the pcie connector I used one pair for the bed, one for the hotend, and one for the cool block fan. I opened it up and unsoldered all the other wires I only kept the pcie and the two to get it to turn on. I actually got this as a refurbished one for 25 dollars so I don't think it's worth not moding it to keep the warranty or something. The Corsair psu is great it's silent and cool.

---

Newbie with Folgertech 2020 i3.

I have the Thermal take smart 500W so it should work fine, which it does. I just have to find a way not to burn up wires perhaps using more of the 12v combined. I don't think it's a big deal to leave wires you don't use or use extension cables but obviously I'm not doing it the right way.

Quote
voyager
Hey dude,

I also trust a good ATX PSU way more then a Chinese hung low brand.

My Corsair VS450 has one rail with 34 amps, it had 12 12v cables, the 6 pin PCI-E had some thicker cables.
I wanted to make a nice adapter cable, but there are so many ATX revisions that it remained unclear how much a connector could handle.
And then you have 4 pin connectors with normal pins, gold pins that could handle more etc, in the end I cut of every thing I did not needed.
Made 2 groups with the 12v wires 8 for the heat bed and 4 for the hotend and electronics and soldered 2 cables on them.
I wanted to solder them directly to the PCB but I could not get it hot enough, lead free solder pfff :-)

It works very good,

Take care.



[attachment 77610 20160506_011754.jpg]

Hey Voyager,

If I decide to cut the wires, what did you do to get yours to look so neat? It looks like you bundled them inside the chassis with your wire coming out. What gauge did you use? I suppose the other option would be to solder them together as a bundle and wire that directly into RAMPS.

I used 4 mm I believe but with future upgrades in mind. One pair can handle 20 Amps@12v for 1.5 meters.

First I cut all the wires I did not needed only 12x12v 1x5v ground and PS-on remains.
I wanted to de-solder them but my Iron could not get them out so I cut them at about 8 cm, spit them in 2 groups soldered them together
and then soldered the 4mm wires to them, you still need a lot of heat to get a good connection. Some extra flux will help. After that I used several layers of heat shrink tube.
Made a strain re-leave from some rubber and tie-ribs.

There are online amp/volt/wire calculators that will give you the exact thinness you need.
Make sure you cut the wires you don't need really short inside the PSU so that you don't short out anything.

Also try to find out if your psu uses 1 or 2 rails I don't know what will happen if you connect the 2 together.

Thanks. I'll figure out what to do. I may just keep the original wires, combine them, and just go direct into RAMPS. It's not as clean as yours, but then again I don't have to worry about the extension wire gauge.

I had the issue of using a soldering iron on a PCB with RAMPS, and it wouldn't melt the solder. If you melt non lead solder over it, it will all heat up and melt allowing you to pull the wire. I did this with a MOSFET replacement on RAMPS.