SG-2000 MANUAL
192
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
23.4
HEAD CPU and MAIN CPU TESTING PROCEDURES
This section describes the test procedures for the SG-2000's Main CPU and Head CPU
subassemblies.
23.4.1
Required Testing Equipment
HEATH KIT IG-5218 Audio Signal Generator or equivalent
Power Supply Capable of at least 2 Amps at 13.6 Volts between the SG-2000
and the PS-30
Connection Cables; CPU extension cable
Remote Head Cable
DMM
SG-2000 Head
SG-2000 Chassis
Oscilloscope
Microphone PTT Toggle Switch
Digital Logic Probe
PS-30
SGC 6805 ports test board, with software
Head CPU bare board sample
Head CPU functional sample
Known good set of socketed ICs
23.4.2
Circuit Description
The Head Processor CPU is a one page schematic, J30100935.
The Head Processor board uses the same Printed Circuit Board (PCB) as the
Main Processor board. The two processors communicate with each other over
the SIN and SOUT lines. The main functions of the head processor are to
control the display, keyboard and audio levels. This is all done in software on
the MC146805E2 microcomputer. The software resides in EPROM on IC16.
The Main Processor is a two page schematic, J30100930.
The Main Processor board uses the same PCB as the Head Processor board.
The two processors communicate with each other over the SIN and SOUT lines.
The main functions of the Main Processor are to select the proper frequency
and to control the various modes of the SG-2000.