Benchtop Power Board ATX 24 pin breakout screw terminal block - PC PSU Testing

[Kiriakos GR]

I have started the planning of a new project here, this includes the use of ATX 24 pin breakout board with screw terminal block.
( I did my choice again by reviewing photographs of all over the planet earth, because such PCB designers they lacking skills at proper product description.)

Generic description: 24/20-Pin ATX Computer Benchtop Power Supply Board Breakout Adapter Module 
Price when market was stable 3$ USD, now its double.

Spesific PCB this is not 1:1 voltage rails wire to its one end point = screw terminal block

For example 3.3V rails (three wires at right side of ATX plug) they are sorted at PCB connector side.
Fourth 3.3V wire this is sorted over the PCB with the other three 3.3V wires.

Another detail hides at screw terminal block specifications.
Voltage rating (UL/IEC): 250V
Current rating (UL/IEC): 16A
Contact resistance: 20 mΩ
Wire gauge: 22-14 AWG  --- 1.5mm
Wire strip length: 5 mm
Thru hole pin 1.0 mm
KF301-4P 5.08mm 4 Pin Connect Terminal Screw

ATX - wire - Molex - limits
Actual ATX PSU per wire DC current this is up to 10A
Actual MOLEX per pin DC current limits this is 5A continues, and 7A for dynamic loads (non continues). 

four pin header
They are seven of them, and not documented at all regarding their output.
Some of the headers have all pins sorted, some others do not.

To be continued.... ( I am currently waiting for PCB arrival, and I will explore more details as soon it arrives).   

[Andrew-88]

This must be the most awkward designed PCB.

12x  GND screw terminal block

2x  3.3V screw terminal block
4x  12V screw terminal block
6x  5V  screw terminal block
--------------------  Total  12 active

13x  GND pin header

6x  5.0V pin header
4x  12V pin header
2x  3.3V pin header
1x  -12V
1X -5V (NC)
-------------------- Total 14  active

Exclude  1X -5V (Nothing to connect)  and the math this is 13x GND plus 13 active.   

If you are up to make a PSU loader, then you need to solder two additional 3.3V wires directly under the ATX connector.
But if you do trust the screw terminal block DC current rating ? then you may use it as it is now.

 

 

[Kiriakos GR]

More or less your calculations  they are correct. 
Someone thought the 5.0V rail this be as more popular one,  for Arduino or other application.

I did a color map for me, so to better understand the rear PCB.

About screw terminal block DC current rating, I would worry mostly if the two wires (3.3V) these can handle the heat, at up to max load of 15A.
The plan it is a PSU Loader along DC Volt measuring harness, that will replace my first revision.   
   

[overvolt]

I am counting the required female connectors for this project.   

ATX 24 Pin = ok = for 12V, 10A safe load
CPU 8-pin (4+4-pin) = ok  = for 12V, 20A safe load

You will need to get two female PCI-E connectors (6 pin), and this setup will be complete.
For 12V, 30A safe load.
All wires sum = 60A continues (if you plan to go that far). 

[Kiriakos GR]

Sea Sonic told me that for load testing I should use 80PLUS load testing ampere per rail specification.
I did significant and a time consuming research so to discover the appropriate documentation, and I did.

One step at the time, let's hope that this PCB will be delivered with out any extreme delay due the Greek post office to me.
We are in August that everything moves sluggish or not at all.   

[Kiriakos GR]

Today I had PCB delivery, after 41 days by using Speed-pack economy after two years of time.

From the beginning I had one major doubt about this gadget, and this came true.
ATX pins in use these has useless manufacturing standards, all metal pin has close to half of the required thickness, of pins found over a regular motherboard connector.

This PCB it is useless for load testing, unless the ATX plug this is replaced with a real one (this be salvaged from an old motherboard).
In conclusion, this thing as is, it is unable to tolerate any significant load over the 1A per pin.     
 

[Kiriakos GR]

Product design myth busting time.    ( ITTSB.EU Exclusive !! )

(At factory soldering, some one add two drops of some sort of Glue (Top side) = hard to remove residue)

[Kiriakos GR]

Time for reincarnation in to a serious Benchtop POWER Board.    

Now we are back in business, with gold plated and certified ATX connector onboard. 

[Kiriakos GR]

Electrical testing = Pass  

But the Asian designer of this PCB, he did nothing so to use the +5VSB output.   

2x  3.3V screw terminal block, instead of three this is another fact too.

Thanks God, that everything else they are in place. 

[Andrew-88]

So the "original" ATX plug over this PCB its just a piss-poor made imitation.
Which this even melted (be destroyed) at the desoldering attempt. 

With all added upgrades by Kiriakos, this thing now become as bulletproof 
So the magic at high power connector, this is the use of pin which these resemble to hollow shaft instead of solid pin.
I am now starting to think that hollow shaft pin this is much more mechanically flexible so this to slightly rotates if needed, for best electrical contact with the female pin. 

 

[Kiriakos GR]

So the magic at high power connector, this is the use of pin which these resemble to hollow shaft instead of solid pin.
I am now starting to think that hollow shaft pin this is much more mechanically flexible so this to slightly rotates if needed, for best electrical contact with the female pin. 

Identical thoughts here, an new property of mechanically flexible pin this could be, this retaining good contact with the female pin, at all range of temperatures.
And possibly the male pin this fine adjust it self, no matter of rotation force this caused by the wire attached over the female pin.

High-End ATX male connector housing, this also includes ventilation holes, either way they are there many product design details that only expert eyes can see.    

Thanks mate!