SG-2000 MANUAL
186
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
Using the multimeter, test each test point for the following voltages:
Cathode D1
13.6 VSW (same as power supply)
Output IC1
8 VG +/- 0.3 V
Output IC2
5 VG +/- 0.2 V
Output IC3
5 V +/- 0.2 V
Input
Ground
Output
Top View
IC1, IC2, IC3
Pin 1 IC12D
V REF (4V +/- 0.3V)
23.3.4
LCD Display Test
The Display Test Chip has a special program to exercise the LCD (liquid crystal
display) by sequencing through all of the possible display outputs. The
sequence is reset to 1 whenever the power is turned off. All keys on the head
are disabled except for the following three:
The POWER key functions as normal.
The VOL. key starts the sequence or resumes the sequence if
paused.
The six key pauses the sequence.
Press the VOL. key to start the sequence. Look for imperfect appearance of
digits - digits continually on or off, not complete, etc.
Pause the sequence if any of the steps do not provide the expected output and
troubleshoot the problem.
Turn off the radio and then the power supply.
23.3.5.
Receive Audio Test
Setup - See Configuration schematic.
Remove the Test Head Microprocessor With Display Test Chip and replace
with Test Head Microprocessor With Normal Chip.
Connect the Display RX Audio Test Fixture as follows (see setup schematic):
One banana plug to the audio signal generator sine wave out.
One banana plug to the input of the distortion analyzer.
SPKR connector to B.U.T. J5.