All posts tagged FVS-1

Oberheim Four Voice (FVS-1) Restoration – Part 8: The SEMs


In the spirit of saving the easy stuff for last (…or so I thought), I tackled the restorations of the four Synthesizer Expander Module (SEM) units.  These were more work than I had anticipated, but then again I opted to completely disassemble them, clean, re-cap, and repair any issues along the way. Fig. 1 – […]

Oberheim Four Voice (FVS-1) Restoration – Part 7: The Programmer


In 1976, the Four Voice began being offered with a programmer module.  Oberheim’s  patch storage implementation was a bit different from that of the microprocessor-controlled polyphonic synths to follow (Prophet-5, OBX, etc…) in that it was capable of  multi-timbral storage/recall of sounds.  In other words, each SEM could be setup differently using the programmer’s controls […]

Oberheim Four Voice (FVS-1) Restoration – Part 6: Cosmetology


I’ve been making some progress on this restoration, and thought I’d lump together a bunch of the more superficial, cosmetic-oriented work in this post. While I’ve had the synth chassis separated from its roadcase, I felt that it would be a good time to freshen things up a bit.  The I/O and power supply panels […]

Oberheim Four Voice (FVS-1) Restoration – Part 5: Keyboard Rehab


Forging on ahead, I felt it was time to give this keyboard some new life.  The bushings were pretty much shot, and several were starting to crumble away – yielding the all too familiar snaggletooth keys and loud metal-on-metal action:     Getting the Four Voice’s keyboard assembly out involves excavating the synth from its […]

Oberheim Four Voice (FVS-1) Restoration – Part 4: Hearing Voices


Now onto the fun stuff…  I’ve been seriously digging this thing even as it limps along with two-voice polyphony, but its time to hear a happy quartet of SEMs! SEMs 3 and 4 were not firing from the keyboard, and the continuous assignment mode would only step between SEMs 1 and 2.  Between all of […]

Oberheim Four Voice (FVS-1) Restoration – Part 3: The PSU


  Before venturing too far down the path of sorting through the faults, I wanted to first ensure that the power supply was in good working order – that the power output was clean, and that the rails were putting out the correct voltage. There are a total of six capacitors on the PSU board […]

Oberheim Four Voice (FVS-1) Restoration – Part 2: Modification Removal


Well, where to begin… I thought I’d start by tracing out and removing the modifications.  Overall, the mods looked to be in a questionable state, and I felt it would help in troubleshooting the primary issues if I could rule-out the modifications as a contributing factor. The “Mediamix Triangle Mod” board was held in place […]

Oberheim Four Voice (FVS-1) Restoration – Part 1: Introduction


I’ve been fascinated by this synth most of my life, and I finally got a chance to lay hands on this one in June 2011. In or around 1975, Oberheim released the four voice polyphonic synthesizer (dubbed the FVS-1), which was basically comprised of four Synthesizer Expander Modules (SEMs; keyboardless, monophonic synths that were originally […]