I have an N3301A electronic load mainframe, with a N3304A 60 V / 60 A / 300 W module. When the mainframe starts up, there appears to be about 4 different noise levels, as the fan speed increases. My unit is staying on the loudest, even if there's no power being dissipated in the module.
I'm wondering if this is likely to be a fault on the mainframe or the module. Needless to say, I don't have another mainframe or module, so can't make any comparisons.