RM850 yes, the infamous one

[vitriol218]

Greetings,

To keep the long story short RM850 having zero rpm fan "feature" managed after couple of years to "fry" high voltage capacitors (correct me if I'm wrong), I wasn't the one repairing it. So the PC was impossible to turn on, altough once it's booted, never had any issues. Stress testing, games etc.
4790k@4.8
GTX970 G1 (now 3060Ti)
Now we all know why this had happened, and I do believe that I won't be able to reach "threshold" where the fan starts spinning so is there anyone who can help with modding so the fan spins on lower load? I don't want to throw it away, but I had to buy used Seasonic650W while this one was serviced.

What do I need to do in order (tried searching around the grid, found nothing) to mod the (?)attenuator/potentiometer(?) to get the fan spinning at lower load. No reason to sell it, nor would I want to explain why was it opened. Basically 200e initially, costed me 20e for repairs, then 50euros for used Seasonic. Nasty Corsair 🙂

Thanks!
 

[LeDoyen]

do you switch off the PSU after you turn off the computer? I don't see how else you could fry components on the primary side.

Usually, components die there because people power off the PSU everyday. That tends to kill them pretty quick.. i heard some died in 6 months, others had them give up after 2,5 years.. just from what i saw here on the forums.

If this is something you do, well, not doing it will make the PSU last a LOT longer, beyond its warranty period.

If not, regarding cooling, an easy way to get airflow is to install the PSU fan up in the case (if it's a typical case with PSU shroud).

The case airflow will get some air going through the PSU, and the heat from the components will rise AWAY from the PCB. That will decrease its temperature without having to mod the fan control.

[vitriol218]

Hey LeDoyen,

First things first, thanks for the effort. However, nah mate, PSU was bought in 2014-15. My PC was/is working 24/7, and I'm aware what can happen to more "sensitive" components if you constantly turn off your PC. Although in last two years, I was three months away couple of times, and last time I wasn't in the country, it was plugged off from the outlet, well everything was. It could have happened before, but "it" decided this last time. It was one of the "big" and "smaller" capacitors that gave up on me. As a service dude said, they regulate the high voltage input. So it was basically working without cooling for the past 8 years...I guess it was about to happen.

Now when it comes to positioning, even though I overpaid for it (Carbide Air 540 doesn't even have glass and really low quality plastic), again, thanks Corsair 😁, I love this case. (Had Antec P series, I know what quality feels like) PSU goes in the second, right-side chamber and doesn't have any fans there.
I guess I could drill holes on the side, "mod" a noctua in and connect it to 4-pin molex or Kraken 3-pins that I have. Although, I'm afraid there's not enough space between side grill and PSU for 120mm fan. The main problem is that PSU leans on motherboard black-plate and that's where huge passive radiator (inside the PSU obviously) is located. So PSU doesn't have any air flow and a fan that isn't spinning.

If modding PSU is possible, I would love to hear someone savvy from Corsair, this is "their" community after all, it would be the best possible solution. Looks like new as well, since the fan never turned, there's not a single speck of dust.

Cheers all!
 

Edited August 12, 2022 by vitriol218

[LeDoyen]

ah if your PSU is that old then it's normal wear of the caps. That's why the PSUs have a warranty of 8 - 10 years.

Even if the PSU is not used, electrolytic caps age so your PSU just reached the end of its tether.

Indeed recapping it would give it a new lease of life.

And forget drilling holes ^^ it's fine as it is. 

Usually Corsair recommends getting a new PSU when they reach that age, because even if the caps don't actually blow up, they are so degraded that they are way less efficient at smoothing the current, and you end up with a ton of ripple on your secondary side, that can cause more stress on your components VRM and even start causing crashes with no causes apparent to the user.

 

Edited August 12, 2022 by LeDoyen