Moog Minimoog Manuel de service télécharger pdf (Page 5)

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The external pre-amp is a three transistor high-gain amplifier. The output of the pre-amp is

monitored by an overload indicator. The overload driver circuit is a Schmitt trigger which turns

the overload light on when external signal levels become excessive.

The first and second voltage controlled amplifiers are two nearly identical circuits. Their gain is

controlled by varying the voltage which supplies the current source transistors. A buffer or

output amplifier follows the second VCA stage.

The A-440 reference source is a highly stable Wein Bridge oscillator circuit. It produces a

somewhat imperfect sinewave which increases its harmonic content. These harmonics or

overtones assist in tuning to the reference, especially when the source being tuned is one or two

octaves away from the reference frequency. The output of this circuit is coupled to the VCA

buffer amplifier.

93-118 Rectifier Board

This assembly contains the input bridge rectifier diodes and the unregulated D.C. filter

capacitors.

93-060 Left Hand Controller

This assembly contains the PITCH wheel, MODULATION wheel, GLIDE and DECAY

switches, and two jacks for remote switching of glide and decay. The PITCH wheel has a

mechanical detent which allows it to be easily returned to a pre-set tune point.

To service this assembly, remove the two mounting screws and lift the unit out. All connections

to this assembly are through a 12 prong plug to simplify servicing and replacement.

93-061 Keyboard

The Mini-Moog keyboard is a standard three and one-half octave removable sub-assembly. All

electrical contacts are gold plated for high reliability. The keyboard is held in place by four (4)

mounting screws which are accessible when the bottom cover is removed. All connections to

this assembly are through a 6 prong plug to simplify servicing and replacement.

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Moog Minimoog Manuel de service Page 5