Corsair CX600 Tests Fine

morningster

morningster

morningster

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Yello! Bought a nearly-new Corsair CX600 and tested it with my multimeter (PS-ON shorted to GND) before putting it into my Lenovo Booststation eGPU enclosure (ITX type format).

On testing without load, fan spins up as expected, all voltage rails (on MoBo 24-pin, PCIE 6+2 pin & CPU 8-pin connectors) test fine within ATX tolerances...

When I connect the Corsair CX600 to the eGPU, the fans (PSU fan + enclosure fan) power on but that's all that happens... Checking voltages now, the MoBo 24-pin connector's 12V and 5V supplies are within tolerance but the 3.3V is well under spec at a max of 2.4V! PCIE and CPU voltages all test fine.

The eGPU contains a Sapphire Pulse Radeon RX 6600 XT gfx card with a single 8-pin power connection; fans don't spin up, eGPU is connected to my PC (via Thunderbolt 3) but Windows 11 doesn't detect the card.

This problem does not occur with the original eGPU PSU, a crappy 500W LITEON. Everything works. Only issue is some kind of signal noise on high demand (AAA game title) which causes stuttering in-game (other people have sorted this out using a better PSU).

If there's a bad ripple problem I don't have a scope to check that. I guess the low CPU 3.3V supply is the culprit?

Not an electronics guy so pardon my ignorance: is this likely a simple capacitor replacement issue for the 3.3V rail, a controller issue or something else? Could this be a problem with the SENSE pins?

Might it be worth doing a little DIY or should I just chuck this?

Thanks.


(The seller of the PSU, who seems decent and has a 1000% eBay rating, refunded the sale without my having to send the unit back. I wonder if the unit was damaged in transit.)
 
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Thanks Micky.

So not a straightforward replace / solder jobbie, it seems?

Yes, tried the eGPU mostly to run Elden Ring, which is supposed to be a CPU-intensive game (my laptop has an i5 12500H, also 16GB RAM, should be alright on that front). RX 6600 XT is not a power hungry card, as you imply, but when I get to certain areas in Elden Ring, even just looking around causes stutter and the PSU makes a funny buzzing noise at the same time.

Another person on Reddit had the same problem and resolved it with a new PSU (SFX form factor) but it's a Frankenstein fit so I tried to be clever and get a PSU with the same ATX format and non-standard power socket placement as the eGPU's LITEON; I would only have to remove or internally relocate the Corsair's power button as the LITEON doesn't have one.

Back to the drawing board...
 
leezer3 said:
It's far more likely the CX600 is fine, but just doesn't like the external enclosure.

Probably if you put a load on the 3.3v rail it'll pull up to something more sensible.
Click to expand...
Hello leezer3.

I've never heard of a (sufficicently-rated) PSU being incompatible with a desktop of any kind? Not a PC builder, so what do I know, but seems weird...

Isn't the drop to 2.4V on the 3.3V supply upon load sufficient to prevent operation?
 
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