I recently picked this 70s Oberheim SEM up on flea bay for cheap because it had dodgy pots and switches, but after receiving it, disassembling it and thoroughly cleaning some grime from the board with alcohol and then cleaning the pots and switches with proper cleaner and then giving them 100 turns and flips each she works like new. This module was Oberheim's 1st synth and it was meant to expand existing performance synths with an extra syncable, independently programmable voice via CV/gate. Mine is the common 2nd version, the 1180 model. The 1180 is the basis of the 2 voice, 4 voice and 8 voice performance synths. The thing has the great Obi filters that are less steep than a Moog or Arp. I have used this a little bit slaved to my Studio Electronics MIDI Moog to create Some Oberheim 2 voice diatonic patches with the SE1's fitler set to Oberheim mode and it sounds great. However, the SEM is a 70s synth and the VCOs suffer from considerable drift so it can sometimes be dodgy when recording long passages depending on the weather. Its lack of stability can thicken parts in unexpected ways, but some days the drift becomes unmusical. My original SEM is also noisey and I find myself running it SEM tracks thru denoising software to remove a lot of the unwanted hiss and the slight hum. It probably neds more extensive servicing.
Its a cool piece to have, but with Dave Smith and Tom Oberheim reissuing Obis now with modern, stable Oscillators this piece is only for afficianados. I would recommend new guys in search of the early Obi sound get a reissue keyboard model, a studio electronics boomstar or one of SE's other Obi flavored options. I am considering servicing and reselling it to buy a reissue or boomstar with money left over. However, it has its vintage charm so we'll see. Its the only synth from this seminal era of synth design I own so I may put up with its flaws just to have some legit vintage quirkiness in the arsenal.