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Homemade watercooled ATX PSU 400W

My case had a Codegen 300W ATX PSU See name plate it has a low cost solution retifiers,
See or Here I will not recomend such cheap PSU types to be used or modified.

I found a new 400W ATX PSU, also a cheap model, then I tested it:
It has the most powerfull retifiers and power transistors I have seen in a long time :-)
Also output voltages was more stable and acurate compared to other PSU I have measured.
400W PSU ordering and price info see here

Here it is, before opening and testing.

The circuit board looks traditional nothing special or fancy,
It looks like it is possible to remove the two alu heatsinks and mount something else and better :-)
The EMI filters is not mounted on this main card, but on another small board, at the input power plug.

I have mounted the EMI filter components on the main board, and removed the EMI board from the power plug

Here is the output retifiers, the biggest is for the 5 volt.

I have glued a LM50 Temperature sensor in the hottest component, the 5 volt double diode.
Now I can measure before and after temperatures to prove the efficiency of watercooling.

This little ugly thing is the PFC coil,
it will be removed due to the fact that it increase power loss and makes a loud humm noise.


I had to unsolder the two bit capacitors, else it was impossible to reach the transistors

130 x 75 x 2mm cu plate, and 12/10mm copper tube

I used the original alu heatsink as a master, so I could drill the new holes exactly the right place

Soldering was not complicated, but you need alot of power, 200W soldering iron is minimum !

Temperature sensor, so I can prove the effiency of this watercooling PSU

To cool the transformator also, I glued two small copper plates, from the trafo to the copper tube
The gluing part was done last, after a quick test of the PSU :-)

Be carefull to mount the capacitors righ way again, note CON2 is shorted, where the coil was connected.

Here is the homemade brass fitting for the thick output hose

The water inlet end outlet, was soldered last, using a wet towel to cool down the main copper part

Here is the water inlet, comming from the inside of the PC,
some ATX cases have PSU mounted upside down !!compared to the old AT style cases, remember to check this !!

Big output to big radiator

Finnaly the AC output will be modified like this

Here the AC output ON/OFF switch has been mounted.

The powercord to the waterpump is soldered inside the PSU output connector,
Now the pump will always be on, if the PC is ON, nice and simple.
See test results

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