I have Chieftec GPA-400S8 400W power supply.

I tried to connect many of its wires to multimeter and turned multimeter to 20V but it always showed 0. multimeter measures batteries okay.

If i want to get 12V 6A out, what wires i should use? It has all kinds of ATX, PCI Express, SATA etc plugs. Thanks

It has:

 

See the picture below. You need to connect pin 14, PS_ON to COM to switch it on.

 

Any Yellow and Black pair will give you 12V DC, as said also join the Green with any Black to power it up.

 

Some PSU's does not regulate the 12V bus or stays powered ON if the 3.3V isn't loaded upto a specific value.

 

Some PSU's does not regulate the 12V bus or stays powered ON if the 3.3V isn't loaded upto a specific value.

This is true. It may need a minimum load, although the recent ones I have had dealings with have not needed that.

 

Short pins 16 (the only green wire) to any common (black) like pin 15. This is how a PC can remotely turn these things on.

 

Thanks. I did not know about connecting PS_ON to COM.

Since i connect this power supply to peltier refrig thing with two fans and it needs 12V 6A, i'm not sure do i need unusually thick wires so it can handle 12V 6A? I have things like "10253 XT60 Male w/ 12AWG Silicon Wire 10cm (5pcs/bag)" etc. Or can i just use any thin wire i have here? Thanks

 

There is a table of current ratings here - look at the chassis wiring column. 12AWG is good to 41A so it will definitely be OK.
"Any thin wire" all depends on how thin

 

What happens if i use way too thin wire? Is there fire hazard?

 

What happens if i use way too thin wire? Is there fire hazard?

Potentially, yes. Wire that is way too big is better than wire that is way too small.

 

I have it now wired, wire is quite thin but planning to replace it later with thicker wire.

Small fan don't work. Well it worked once. And entire thing sometimes it works, sometimes not??

 

If you mean the fan in the power supply, I believe it is a controlled fan, so it will only run when cooling is required.
Do you have a secure connection to the PS_ON wire?

 

You're best to join all the Yellows together, and all the Blacks together, then you can draw upto the maximum current rating on the psu.

 

Do you have a secure connection to the PS_ON wire?

I have soldered together PS_ON (pin 16) to COM (pin 17).

You're best to join all the Yellows together, and all the Blacks together, then you can draw upto the maximum current rating on the psu.

So i solder together yellow pins 10 and 11 and then all the black COMs including pin 17 which i already used? Do i solder all black wires or since there is two yellows, is two black wires enough? I have the connector on left:

 

I have now connected to refrig blue and all yellows.

Also since black ones are COM and blue is -12VCD, should i connect all these together??

 

You don't need the Blue -12V, leave it alone, just connect the Yellows together and the Blacks together, as there are only two Yellows just connect two Blacks, and use those as your fridge supply.

 

Thanks. So i connect just two black to refrig. But do i need to solder rest of the black ones together and leave it unconnected?

 

Thanks. So i connect just two black to refrig. But do i need to solder rest of the black ones together and leave it unconnected?

No, you can leave all but the two yellow and two of the black wires and the PS_ON disconnected

 

Thanks. I have now wired like that but absolutely nothing happens.

Maybe i have destroyed power supply and/or refrig. How i can test if power supply gives out 12V?

Now it shows 0.0 in multimeter when multimeter is turned to 20V DC.

 

Are the black and green shorted together, is the fan running ??