instead of clogging up the PSU modding sticky I decided to post this in its own thread (although this will be linked to the sticky). I did a fan swap for the PSU that came with the NSK6500. It's a 430W version of the PSU shown in the SPCR review of the Antec NSK2400.
EDIT: I kept talking about the 380W version, but it is 430W.
First some pics of the internals:
Here's a pic of the original fan (high speed sleeve bearing by ADDA) and the 2-pin fan connector.
I replaced the connector with a "regular" 3-pin by soldering it in place of the original connector. The picture also shows the fan controller thermistor on the heatsink.
My replacement is my usual NMB-MAT 80M1BX (Panaflo) from Dorothy Bradbury, a medium speed fan with the tacho. I used two separate connectors on the fan, one for the internal fan controller header and another connector for the tacho. The tacho signal / connector is taken outside the PSU and connected to a motherboard for monitoring the RPM.
The end result. I had to remove the fan mounts I intended to use, because the PSU PCB is literally touching the fan frame. It was simply impossible to mount it inside the PSU with fan mounts.
After running it in my new system I'm a bit concerned about the fan voltage. Similar to the SPCR review I cannot the fan voltage to rise above 5V even after extended periods of stress testing. (EDIT: meaning my new system draws below 200W and the fan voltage stays below 5V for those loads). The air coming out of the PSU remains well below <40C, but obviously with a slower fan the airflow is very small.
I have ducted the PSU to the front bezel (see the temporary cardboard duct and the 5,25" cover plate I modified) for cool intake air, but I still may end up using a fanmate to set the fan at ~6V.
The intake area in the cover plate is smallish, but the NSK6500 has a raised front bezel that allows air intake through the sides of the front bezel.
Spank you very much for reading,