Kurzweil SP5-8 Service Manual

Printed Circuit Boards
Function Overview
2-3
U3 is a NAND Flash chip, which is very similar to what is used in memory cards and USB
“thumb” drives. It holds the operating system code, sound programs and setups, and user
data (user sound programs and MIDI sequences). The capacity is 64MB.
U2 is system RAM. After bootup, the operating software executes from system RAM. It also
holds currently used sound programs and MIDI sequences.
Scanning
Software in the operating system also performs scanning of the player controls (keyboard and
pedals) and the user interface (UI) controls (buttons, LEDs, Spin knob, sliders, and wheels).
This is accomplished through a simple, Kurzweil standardized, interface called ScanPort (J7,
page 3, zone D1). Most of the circuits for scanning are actually on the Right and Left Front
Panel PCBs; only a couple of buers (U6, U8), an analog amplier (U9), and decoding logic
(U11) are on the Engine PCB. See the Right and Left Front Panel PCB descriptions for more
details about ScanPort operation.
Synthesis ASIC
Page 2 has the MARA synthesis ASIC, U5. This proprietary, Kurzweil designed VLSI chip
integrates the following synthesizer circuits:
• 64 sample playback channels, each with independent playback rate
• 64 amplitude envelope blocks
• 256 DSP processors, each with independent envelope
• Eects processor with 16 processing blocks
• Patching array for interconnecting the above resources
• Digital audio formatting circuits
The instrument sound samples are stored in Sound ROM (page 4, zone 5D). The standard
SP5-8 has 64MB (only U13 installed) of Sound ROM. Other products using the same Engine
PCB may have additional Sound ROM installed at U14.
The eects processor also uses an external Delay RAM (U12, page 3, zone A4). Pops, audible
crashing sounds, and other extraneous noises are often caused by defective Delay RAM or
connections to it.
D-to-A converter
U15 (page 4, zone D1) is a digital-to-analog converter. It connects directly to MARA on the
digital side and directly to the Audio Out header (J11) on the analog side. Ampliers and
reconstruction low-pass lters are on the Left Front Panel PCB. Although U15 is an 8-channel
DAC, only the rst two channels (L1 and R1) are used in the SP5-8.
A separate MUTE signal comes directly from the CPU to suppress pops and clicks during
power-up and power-down. MUTE must have a low logic level (less than 0.8V) to enable
audio on the Left Front Panel PCB.

Kurzweil SP5-8 Specifications

General

Keyboard number of keys	88
MIDI-keyboard number of keys	- keys
Product color	Black
Pitch bend wheel	Yes
Interface	USB
Headphone outputs	1
Input voltage	15 V
Power source type	DC
Power consumption (typical)	15 W

Weight and Dimensions

Depth	350 mm
Width	1392 mm
Height	120 mm
Weight	21000 g