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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.
Power LED
blinks
1 X
Short on the 30V line
2 X
Excessive voltage at the 12V, 9V, or 3.3V line.
3 X
Fan rotation not detected
4 X
3.3Vdc from the power supply not detected
5 X
Lamp fails to light after TV powers on.
6 X
microprocessor & IC4001 (DG Bd) communicatins
7 X
microprocessor & IC4201 (DG Bd) communicatins
8 X
microprocessor & IC4401 (DG Bd) communicatins
9 X
No color wheel output detected or out of speed
range
none
1. Lamp door switch is open or
2. Open thermal breaker above the lamp housing.
none
No standby voltage detected
Temp LED
Excessive temp at color wheel assembly
Figure 29 - Shutdown Causes
TV Shutdown Causes
Description / Cause
Table 13
35
Varification /
Normal Votlage
Location
P5 /pin 2
0Vdc
P5 /pin 3
0Vdc
P5 /pin 4
0Vdc
DG5 /pin 7
3.3Vdc
DG1 /pin 3
0Vdc = lamp lit
DG15/pin 9
3Vdc = ballast on
DG9/pin 4,5
----
DG9/pin 6,7
----
DG15/pin 4, 5
3 Vp-p = TV on
DG15/pin 7
180 Hz pulses
P4/pins 1 to 2
0 ohms.
P4/pins 3 to 4.
0 ohms
DG2/pin 9
7Vdc (stby)
DG2/pin 1
3Vdc (AC stop)
L/pins 4, 5
3Vp-p
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