July 2020 PSU CORSAIR CX750 Repair - CP9020015 - CWT PUQ-G - Quality Monster

[Kiriakos GR]

I can now announce this repair as truly finished and tested.   

1) I did install the male plug AK-CB8-8EXT at the PSU
2) I came with the idea to use the female plug AK-CB8-8EXT as DC load harness, because of that smart idea ... I tested and the PSU among with the quality of my own wire to wire connection.
3) The test run for approximately two hours,  but the presented measurements they are for the last 1H 20 Minutes.

The 12V rail this is capable for 62A according the specifications, my DC load this is capable of 110Watt and the max stress was at 9.5A , this is 16% of load.
The amazing part this is the Min-Max voltage deviation ( with load - No Load ).
Average value 12,188V
Max value        12,191
Min Value        12,183
This is just 8 mV DC drop, that is totally insignificant. 
The theoretical variation at 12V rail this can be + / -  2% =   12,240  OR  11,995 V
I did also test the +5V VSB Stand-By rail (PSU sleep mode) ,  from the named 3A  the 5V stayed at the specification of  4,90V (-2%) up to 2.5A of load !!   
5,00V  at 1A  and 5,054V at 200mA, No load 5,070V.

In all those two hours the PSU and the cable harness were frozen, among the wire to wire connection which I did with lots of attention to detail.
The final conclusion this is that the specific CORSAIR CX750 - CP9020015 - this is now ready to serve it purpose with max reliability as this is restored up to factory quality standards

By this new experience I am also now aware of max load that its cable harness this can handle.
For example when I did stress with 9.5A two pairs of cables the voltage drop this were a bit higher.

The PCI-E connector this using three pairs and this helps for transfer of up to of 10A with a minimum voltage drop under load.

One demanding hard-drive will use 750mA and in RAID mode this will be double as 1.5A per single pair of wires with four Molex or SATA connectors.
The new conclusion coming from that math, this is that single pair this is calculated to tolerate 3A ~ 4A  with minimum voltage drop.

CPU harness this will aloud 12A with minimum voltage drop.

Motherboard 12V (24 pin)  rail this is two pairs = 6A 

The final estimate of wires sizing and expected nominal load in a chart, this is:  
1 x PCI-E  = 10A
2 x PCI-E  = 20A
CPU  12V Power = 12A
Motherboard 12V = 6A
HDD single wires pair with four plugs SATA = 3A ~ 4A
CDRW or DVD recorder this is 2A its one (12V)  for Molex four pin (At DVD to DVD recording mode the sum this will become 3A)
Three DC fans = 1.5A

         

[Kiriakos GR]

UPDATE (Year 2022): I am now a believer, even the quality monsters they have a date that they must get retired.

I did use the CX750 with my Intel P45 motherboard along Q9560 3GHz quad core, with no problems.

This month I did switch to Intel Z87x motherboard along i7 4770 (4C/8T) and at heavy graphics load the CX750 this simply shutdown
I did some basic power consumption measurements, max load on average 300 watts,  the GPU this is GTX1060 6GB, I am now assuming that this produces DC current spikes at 30% higher consumption of what I can measure with an economy (slow) power meter.

My verdict is that my CX750 of 2013, this is unable today(2022) to handle DC current spikes because it electronic protection circuitry, this is today in huge error, according to original factory calibration.
 
This is a problem which slowly develops at passive components, and especially at the side of resistors.
PSU current shunt this gets out of specification, because possibly the solder in use at the PCB this gets old, and it develops a higher resistance.
Or other SMD resistors at the control circuit, they get out of specification, and the protection control circuit, this receives wrong feedback, and activates prematurely.

We may be able to repair larger power electronics (replacing Mosfet and DC bridges and capacitors), but to restore the functionality of the electrical protection circuitry to factory standards, this is micro surgery that personally I will never get involved.

So I am now forced to declare CX750 as out of duty, when this is to serve i7 Haswell along an GTX1060.