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35
Protection Circuits – Shutdown Causes
Overview
Ant one of the seven TV problems shown in Figure 29 (and listed in table 13) can
shutdown the TV, requiring the TV to be unplugged to reset. A typical shutdown
sequence is:
1. Power-on – Green power LED blinks
2. Relays click on, then off (TV detected a problem)
3. Power LED changes from blink to flashing green or red
4. Reset the latched shutdown section by unplugging the TV.
After the AC relay clicks off (TV shuts down) and before the TV is unplugged, the
microprocessor on the DG board blinks the power LED a specific number of times,
pauses and repeats to indicate the cause of the shutdown.
TV Shutdown Causes
Power LED
blinks
Description / Cause
Varification /
Location
Normal Votlage
1 X
Short on the 30V line
P5 /pin 2
0Vdc
2 X
Excessive voltage at the 12V, 9V, or 3.3V line.
P5 /pin 3
0Vdc
3 X
Fan rotation not detected
P5 /pin 4
0Vdc
4 X
3.3Vdc from the power supply not detected
DG5 /pin 7
3.3Vdc
5 X
Lamp fails to light after TV powers on.
DG1 /pin 3
DG15/pin 9
0Vdc = lamp lit
3Vdc = ballast on
6 X
microprocessor & IC4001 (DG Bd) communicatins
----
7 X
microprocessor & IC4201 (DG Bd) communicatins
----
8 X
microprocessor & IC4401 (DG Bd) communicatins
DG9/pin 4,5
DG9/pin 6,7
DG15/pin 4, 5
3 Vp-p = TV on
9 X
No color wheel output detected or out of speed
range
DG15/pin 7
180 Hz pulses
none
1. Lamp door switch is open or
2. Open thermal breaker above the lamp housing.
P4/pins 1 to 2
P4/pins 3 to 4.
0 ohms.
0 ohms
none
No standby voltage detected
DG2/pin 9
DG2/pin 1
7Vdc (stby)
3Vdc (AC stop)
Temp LED
Excessive temp at color wheel assembly
L/pins 4, 5
3Vp-p
Table 13
Figure 29 - Shutdown Causes