Kurzweil SP5-8 Service Manual

Printed Circuit Boards
Function Overview
2-4
USB Controller
The CPU has an integrated USB controller that can be either Master or a Slave but not at the
same time. Switching circuits (page 4, zone B1) switch between the two functions. In the
SP5-8, the actual USB connector is on the Right Front Panel PCB and connects to the Engine
PCB by two cables.
MIDI (5-pin) Interface
The CPU has an integrated UART congured for standard MIDI In/Out. The actual 5-pin
MIDI connectors and interface circuits are on the Right Front Panel PCB. J31 carries standard
MIDI signals to and from the CPU.
Voltage Regulators
The Right Front Panel PCB brings in the single +15V power voltage from the AC adapter and
converts it to +5V for digital circuits and +/-8V for the analog circuits. These voltages enter
the Engine PCB on J23 (page 5, zone D2). Note that although the analog power signal names
are +12V and -12V, the actual voltage level is +8V and approximately -10V.
The various large chips on the Engine PCB require several dierent power supply voltages:
+3.3V (VCC33), +2.5V (VCC25), +1.8V (VCC18), and +1.2V (VCC12). All of these voltages are
regulated by integrated linear voltage regulators.
U23: +5V (VCC) is the source voltage for the VCC33 regulator.
Powers the CPU, MARA chip, and most of the other digital circuits.
U24: VCC33 is the source voltage for the VCC25 regulator.
Powers the Delay RAM for the eects processor in MARA.
U25: VCC33 is the source voltage for the VCC18 regulator.
Powers MARA’s core logic.
U26: VCC33 is the source voltage for the VCC12 regulator.
Powers the CPU core logic.

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