If your rice doesn’t smell and your water doesn’t smell, I’d be inclined to believe your new rice cooker sucks. Does your rice cooker smell, even when there’s no rice in there? I would sniff the steam vent (not while it’s on …) and anywhere else really to check.
I found this:
You need to clean the rice cooker. Over time the inside builds up a sort of ‘coating’ of the ‘starch’ in rice, and that turns sulfurous after awhile. Get a small can of Cream of Tartar and a small bottle of CLEAR (white) vinegar. Pour the WHOLE CAN of Cream of Tartar in and add two cups of vinegar. Fill with COLD water and then run the rice cooker through the cycle as if you were making rice. When that is done, pour the ‘cleaner’ out, wipe every surface you can inside, and fill it again with pure cold water and do it again. After this your rice should be ‘perfect’ again … but to keep the rice cooker ‘clean’ you should do this ‘cream of tartar-vinegar-water, then plain water’ cleaning AT LEAST ONCE A MONTH …
I personally have never had a problem with a rice cooker, we clean the bowl and wipe the removable ‘ceiling’, and anywhere there is steam-turned-water, but other than that, all of them have always been fine.
This makes me think you have a poor rice cooker; some starches have become stuck somewhere and have rotten. Or if it’s not the rice cooker’s fault, perhaps you filled it up past the max point, and so some rice has bubbled up into where it’s not meant to go?