Roland SH-5 Service Manual

3-2-3. CIRCUIT BOARD ASSEMBLY OP-20
VCO-2, RING MOD.
VCO-2 is an oscillator which is about the same as VCO-1.
With the Keyfollower turned to OFF, the frequencies generated here are held at a constant level and not subject to
follow the keyboard.
RING MOD. (ring modulator) is a circuit for producing sounds of special effect, such as bell-like sounds. The sum
and difference of the two input frequencies are the only frequencies to appear at the output of the ring modulator.
3-2-4. MIXER BOARD ASSEMBLY OP-23
This is the section that decides where the signals coming from NOISE GEN., VCO-1, VCO-2, RING MOD., EXT. IN.
will go.
Also provided here is an amplifier circuit for the signals of EXT. IN.
3-2-5. CIRCUIT BOARD ASSEMBLY OP-21
VCF, BAND PASS FILTER, VCA
The VCF is a Voltage Controlled Filter and can be used either as: LPF, BPF, and HPF.
The LPF consists of a ladder type network of diode chain transistors, and is capable of generating by itself fre
quencies of a wide range so that it can be used to make musical scales following the keyboard manuals.
Band Pass Filter is, unlike the others, a fixed filter and not voltage controlled.
The VCA has its gain under control of the control voltage applied to the base of the current source transistor in this
circuit.
3-2-6. CIRCUIT BOARD ASSEMBLY OP-22
AR, ADSR, FIXED ENV.
The Envelope Generators have separate controls for controlling the elements of the envelopes (ATTACK and
RELEASE for the AR, and ATTACK, DECAY, SUSTAIN:, and RELEASE for the ADSR). The Envelope Generators
are triggered from the Keyboard Circuit gate pulses or from LFO-2, S/H, or EXT.
The FIXED ENV, however, is triggered only by the keyboard gate pulse.
3-3. SUB CHASSIS UNIT ASSEMBLY SU-1 (Including Pack Assembly BX-13)
Located here are the output jacks of SH-5, also with jacks for control from external sources.
3-4. POWER SUPPLY UNIT ASSEMBLY PC-5
This is to produce the regulated ±14V and in order to secure voltage accuracy, potentiometers are provided in this
circuit.
Note that PS-17 is for 100 - 120V, while PS-23 is for 200 - 250V.
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Roland SH-5 Specifications

General

Brand	Roland
Model	SH-5
Category	Synthesizer
Language	English