5/ Moog perfected the Minimoog by issuing a revised osc. circuit board wich gave far improved stability and added a new “buffer board”, wich gave better stability. All Mini with serial number greater than 10175 have the newer osc. board. These new osc board could be installed in older version. Full plastic panel, white ribbed modulation wheels. Serial number 10175-13233.
How can you know if your version is an old one upgraded? The way to check is to look at the metal back cover to control panel. On the right side you’ll see 2 vertical rows of 3 access holes (6) or 3 vertical rows of 3 (9). If your Mini has got 9 holes, it’s a new osc version. But don’t look only at the modulation wheels because they may have been changed. Even the front panel may have been changed (metal/plastic).
All Minimoogs made by Moog have been fitted with regular pointed (arrow) knobs on the octave and waveshape pots.
But, the arrow knobs break very very easily because they're made of bakelite, like old wall telephones. Moog switched to the other kinda knobs for his Multimoog and Micromoog since they are made of plastic, they last longer and they cost much much less! That’s the reason why sometimes the knobs on the octave and waveform pots are the same kind of the ones used by Moog for Multimoog and Micromoog synths but not exactly the same.
The "other" knobs that were used on minis are not the same as micromoogs.They are different altogether. The micromoog used non-setscrew, press-on "half shaft" knobs.All of the mini knobs, whether the familar pointer knob or the "other" type with the straight piece through them, used setscrews and no minis used half-shaft selector switches, so Micro knobs wouldn't fit anyways.
These knobs were a good replacement for arrow Mini knobs too and probably the only ones available at that time, late '70s. Moog run out of stock on the arrow knobs when he stopped Mini and Modular productions.
Aestetically speaking they do not match the original large and small round knobs put on the other Minimoog pots by Moog, because of the drastically different shape and for the round silver disk in the middle which does not shine like the one on the bakelite knobs. And plastic too does not shine like bakelite. Moog would have never switched one kinda knob only on his Minis. He would have switched the complete set of knobs, as he did for the Multis and Micros. All Minis produced have been fitted with bakelite knobs.
Moog produced more than 13,000 Minimoogs. Some have been fitted with those plastic knobs by the owners after they got broken. There are 7 in the 4XXX range. And there could be 10 in the 5XXX range and 23 in the 6XXX range and 14 in the 7XXX range... all together could be a couple hundreds Minis. Is less than 2% of the total production. Pics of theese knobs at :
There's actually all sorts of little changes here and there to the boards and everything else as production went higher. Nothing really stayed constant in any section through production.
Also, and rarely remarked, is that Moog changed the resistor feeding the filter through production.This lowered the distortion on later units. Several changes were made on this.
Other changes from early ones:
1/ later models had switchable power,
2/ very late models had some of the edge connector pins (on the sockets) gold plated to increase reliability, better resistors, etc.
3/The mod section cinch jones connectors were also gold plated in the last rev or production or so.
4/ The rectifier board in the mini went through at least 3 changes too.
Very early metal panel minis used all sealed pots, later ones used both open and sealed pots.
5/ Later minis also used double-contact rocker switches and wired them up in double where possible to improve reliability.
6/ Later minis had the brackets for the pots in the mod section with pressed in nuts, eliminating the separate washer and nuts used on the earlier ones.
7/ The early minis didn't mount their power transformers very well and they could move or break off- later ones added a piece of aluminum bar to help this from happening.