Corsair HX 750W - DC Leakage at 12V Output Rail in Standby Mode

[прямо]

Just received it today from a friend.
Auto shutdown by the supervisor IC because of an under voltage condition with 12V output rail (dropped to 10.5V)

The same rail also does this when the PSU is in standby mode.

https://ibb.co/5TBkg66

The leakage keeps climbing at a steady rate but slowing down when it reaches over 800mV or so. I didn't measure exactly at what value it stopped or if it's even stopped at all.

What could have caused that?

First time I have seen such behavior.

3.3V and 5V rails don't have the same symptom. No output when in standby mode.

[stj]

strange.
if you put a load on the 12v rail does it still happen?
all i can think of is energy from the stanby transformer being magnetically coupled to the 12v transformer if they are too close.
if thats true then the current will be almost nothing

[прямо]

I found the under-volting problem, it was caused by one of the output caps having a high ESR. I replaced it and 12V is back to 12V.

PSU can start without shutting down, but this DC leakage issue still exists.

It also seems to settle around 750mV or so after being left alone in standby mode for awhile.

Other than the 12V DC fan that it comes with, I haven't test the rail with any load, but it's pretty stable at 11.99V ~ 12.00V