Gen 6 ATX PowerSupply

I found this old power supply in my basement and was wondering if i could use it , its 450W, and i think its atx 2 as the big molex connector has a detachable 4pin plug. Im also not sure if im supposed to collect all the 12V wires and solder them together , or if i could just use the extra 4pin 12V wires ?

also this is for the GEN 6 electronics.
pics

As Gen6 requires just 50 Watts (no heated bed), or 4 amps at 12V, take any of the connectors. A single connector is sufficient. Don't forget the clamp from pin 14 to GND to switch it on and a load resistor on 5V. An old CD or hard drive makes a nice load as well.

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ive followed the instructions on these 2 pages
forum post
from the wiki

and neither mentions a load resistor . all they say to do is connect the green to a ground , and on pin 11 make sure the brown sensing wire is connected to an orange +3.3(mine already has a brown and orange connected in pin 11). so would i need to hook up a hard-drive to get it working ?

ok , i just connected the green to a ground , and the powerSupply turns on (fan is on and correct voltage through wires) , but i havent tested it on the Gen6 board yet.

Edited 2 time(s). Last edit at 04/13/2011 02:14PM by Rooski.

Usually the 12V line runs low if there is no load on the 5V rail.

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[www.hydraraptor.blogspot.com]

what resistor should i attach to the 5v then? as i dont want to have a hard-drive sitting there for nothing.

also putting a load on the 5v(hard-drive) doesnt seem to change the voltage at all , on my meter(not digital) the 12v line stays at 11v , same if no load.

Edited 1 time(s). Last edit at 04/13/2011 04:38PM by Rooski.

I think the recommended value is about 10 ohm 5W. You might also need a load on the 3.3V line if the 12V is still low.

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[www.hydraraptor.blogspot.com]

I'm using an ATX power supply and I didn't have to connect a dummy load to the 5V supply to turn it on. The load on the +12V leg from the stepper motor controllers (3x Gen 3 stepper controllers or 1 controller with 4 Pololu boards) is enough to be able to turn it on.

One disadvantage or advantage with this is that if I issue an M0 command to disable the steppers, the power supply goes off. I then have to disconnect and reconnect the PS_ON pin to turn it back on after enabling the steppers again. I use this sometimes if I leave a long print unattended so it shuts itself of in the end.

Do you actually get 12V on the 12V rail though. I have seen it as low as 10V without a dummy load and that makes a big difference to the extruder heater.

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[www.hydraraptor.blogspot.com]

I think the 12V regulation will depend on the design of the Switch mode PSU hence this variation people are seeing.

All of the PC Switch mode supplies I have used so far have been very old power units. I have not seen a lower voltage on the 12V line either. It could possibly be only on some of the newer Switch mode designs where this shows up as a problem maybe?

I curently do not use a PC supplies as I prefer to run my electronics on a higher voltage of 24V to 30V.

It also means the supplies are lower cost, lower profile, less wires & looks neater.

I have not changed from a 6.8ohm element / resistor on the extruder with an 8ohm heated bed.

I still use the same old PC supplies for other projects I must have 6 or 7 old PC supplies from 100W > 250W.

I don't think I have used a higher watage supply.

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Bodge It [reprap.org]
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BodgeIt Wrote:
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> I think the 12V regulation will depend on the
> design of the Switch mode PSU hence this variation
> people are seeing.
>
> All of the PC Switch mode supplies I have used so
> far have been very old power units. I have not
> seen a lower voltage on the 12V line either. It
> could possibly be only on some of the newer Switch
> mode designs where this shows up as a problem
> maybe?

this PSU isnt too old , id say like 4-5 years , it came with the pc case i ordered , but i already had a nice 600w PSU so it was boxed away.
Im going to pick up a good digital meter today ,and test with different loads, and see if there is a difference.

Lower cost? Where are you getting your power supplies. I haven't seen anything around that will equal an ATX supply for power at the same price.

nophead Wrote:
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> Do you actually get 12V on the 12V rail though. I
> have seen it as low as 10V without a dummy load
> and that makes a big difference to the extruder
> heater.

Yes on both rails. The problem with it is that I think it's well overrated. eEven though they rated it at 18A each, I found that there's up to a 0.3 V drop on both rails everytime the heater comes on. The heater I'm using is the Prusa PCB which has a resistance at room temperature of 1.1 ohms so it should draw no more than 11A . The tip is on the other rail which should draw about 2A. This is well below the rated output for each rail and yet the voltage drop is fairly large. I got it from Microcenter. I can post details on manuf/model if there's interest.

Did some tests with a load on the 5v and 3.3v line , with no load the 12v line reads 12.25V , with a resistor on the 5V line 12V shows 12.35V and the 3.3V line doesnt affect anything.

So im just going to keep my supply as is and just tuck the wires in the case.

Did you have a load on the 12v line?
Under no load for the 12v line you won't see any difference!
So I will ASS-U-ME that you had your electronics running on the 12v when you did your measurements with and without the load resistor.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
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rhmorrison Wrote:
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> So I will ASS-U-ME that you had your electronics
> running on the 12v when you did your measurements
> with and without the load resistor.

i did both, with the gen6 plugged in and without , results were the same.

Edited 2 time(s). Last edit at 04/18/2011 10:20PM by Rooski.

I don't have 10R resistor or less with high watage. I have only 15R 15W. Isn't 15R too high? Current is only 330mA.

It won't hurt to try it.