Yamaha Portasound PSS-190 (1990)
The PSS190 is a "high-performance electronic keyboard" according to the manual, and certainly packs a lot of sounds into a small package. Many of the voices sound like PCM samples of the FM sounds on the PSS-680/780/480/580 keyboard range, but there are also layered and split voices to play with. It also had a slightly smaller-bodied sibling, the PSS-50, with fewer accompaniment rhythms and no drum pads.
This track is on the ALF album...
A few people had commented on the amount of FX I used on the mix for the original video, so here is the honest mix, with the raw sounds from the keyboard recorded into Logic and sequenced, with only a small touch of reverb to give some depth (too dry is no fun) and no other external FX used on the mix. (Well, apart from about 2 seconds in the middle where I stuck a high-pass filter on the bass for a bit of variety).