There is really no need to replace the unit because of a capacitor failure, the other option is to use the 5V input jack on the ISS board and rig either a small 6v solar panel/battery or a small 12v solar/battery and 12/5 or 6 volt converter. This only needs to be a 1.2ah battery system.
And if your ISS just happened to be close to mains power then a 5v power pack (same as the console uses) solves the problem, backup battery then lasts for a very long time.