I have an Iota DLS-75 converter/charger and it has a 24 volt variable speed cooling fan. Needless to say it finally took a dump after about 8 or more years of being on 24x7x365. Easy fix, just order a new fan right? Iota does not have any spare parts that I was able to find, nor does anyone else.
The fan is mounted on the back of the converter/charger. Basically the case is a big heat sink. I unpluged the unit from the 120 volt outlet, removed the unit from the bay wall and the removed the fan. After taking the unit almost completely apart I find the power/ground leads are soldered to the system board. So you need to cut the wires to replace the fan.
I Googled the fan model number and found a replacement for $7 and few bucks for shipping. Simple task of soldering a couple wires and add some heat shrink for insulation.
One small gotcha.... there is one fan mounting hole that does not thread in to the case. So, Iota put small piece of metal on the backside that acts a nut. Really good engineering!
You have to take the fan mounting bracket off to install that screw. More good engineering.
Remount the Converter/Charge and plug it back in. Runs like champ and is whisper quite.