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Diagnostic Procedures
In some cases, the front panel LED will flash a pattern indicating the circuit that
has failed. Be sure to record the pattern displayed at start-up.
Number of
Failed Circuit(s)
LED Flashes
1
Main Micro power
STB5V
2
Scan
Driver 1
Vf5
Vad
3
3.3V S0S
4
5V SOS
P5V
5
Power SOS
Vsus (170V)
15V
20V
6
Fan Stop
7
SCAN Driver 2
½ Voltage
(Energy Recover)
9
SUS Driver
½ Voltage
(Energy Recover)
12
Tuner
Power
UNR21V
UNR14V
+2.5V(M)
+9V(M)
LED indicators on the SS and SC boards alert the technician when a problem
exists. The LEDs should be lit during normal operation, a dark LED indicates that
a problem exists on that board.
Detection
Point
IC9709
pin 34
Vscan
IC9709
Vfo
pin 64
IC9709
Pin 3
IC9709
pin 2
IC9709
pin 63
IC9709
pin 37
IC9709
pin 1
IC9709
pin 61
+9V(S)
IC001 pin
+5V(S)
69
+3.3V(M)
41
Note
Suspected
Board(s)
Voltage
P Board
too low
Voltage
SC Board
too low
D Board
Voltage
P Board
down
Voltage
P Board
down
Fan
Load
SC Board
over
Detect at
IC6581
Load
SS Board
over
Detect at
IC6705
Voltage
Tuners or
down or
PA Board or
over
current
P Board
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