Troubleshooting Flow Chart For Display - Motorola CDM Series Detailed Service Manual

Control Head CDM1250 / PRO5100 / CDM1550 Series / PRO7100 Troubleshooting Flow Charts
2.3

Troubleshooting Flow Chart for Display

Power up alert tone sounds, Volume knob works,
indicator/back light is on, but the display is blank
V5 (against 5V)
TP0973 between
-6V and -7V?
NO
Activity on
Address & Data lines
A0 / D0..D7 / CS1
of U0971?
YES
Check / Replace
C0971 / C0973 / R0972
R0973 / R0974 / U0971
YES
Check LCD Assembly
NO
Check for short
U0831 / U0971
Section 2: 3-5
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