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Lamp Abnormality
■ The Lamp Driving Circuit (
LAMP COVER
THERMAL SWITCHES
SW
K26Z
K26U
FANNET_2
ASS'Y
EXH FANNET
K56A
3
1
K8U
12VA
ASS'Y MAIN
NOTE :
■ At first, the high-voltage pulse (about 8KVp-p) is generated between the
lamp electrodes to generate glow discharge. Then dielectric breakdown
occurs, finally glow discharge comes to arc discharge.
■ After projector turned on, 30 seconds are required until the light output
stabilizes.
■ After the projector is turned off, the cooling fans operate for 90 seconds to
cool down the lamp and reduce gas pressure inside the lamp.
NOTE :
■
Switch
Lamp Cover
Make sure that the lamp cover is mounted correctly. If not or the lamp cover
removed, the lamp does not light for safety.
Check the boss of the lamp cover and the lamp cover switch (SW902).
SW902 -- open : Abnormality
■ Temperature Switches
When the internal temperature near the lamps reaches near 110ºC, the
temperature switches open and 12V_PFC is not supplied to PFC-Unit.
SW903 - SW906 -- open : Abnormality
■ READY (green) LED indicates lamp monitor operation
LED off:
Lamp is being cooled.
LED on:
Lamp is being lit or already cooled down.
Lamp_3 )
example
AC INPUT
K26T
AC108~264V
12V_FN
P_FAIL
GND
3
P_FAIL_FAN
K8Q
5
12V_FAN_C
4
12V_PFC
6
PFC_ON/OFF_CN3
7
PFC_ON/OFF_CN4
1
P_FAIL_CN3
2
P_FAIL_CN4
8
GND
DC INPUT
DC380~400V
1
LAMP ERROR
2
GND
3
BALLAST ON/OFF
4
GND
5
NC
UNIT_PFC3-4
LINE
FILTER
CN5
1
2
H : Abnormality
3
CN6
3
5
4
6
H : ON
7
H : ON
1
L : Abnormality
2
8
L : Abnormality
UNIT_LAMP BALLAST
FILTER
DOWN
BUFFER
CONVERTER
CJ2
1
H : Abnormality
2
3
H : ON
4
5
■ When the tempera-
ture around a lamp
driver reaches 85
degrees, unit lamp
ballast will be shut
down and a lamp
monitor
changes from L to H .
■ The CPU performs an input check by the lamp moni-
tor pin.
■ When the "H" signal continues 1 second or more
continuously, the CPU judges the state to be abnor-
mal.
■ When it has detected abnormal condition, the CPU
turns off a projector compulsorily. And the CPU sets
up the cooling time for 90 seconds.
■ The projector cannot be turned on during a cooling
time.
- 65 -
Troubleshooting
U20B47200
BRIDGE
ACTIVE
DIODE
FILTER
THERMAL
PROTECTOR
BRIDGE
ACTIVE
DIODE
FILTER
THERMAL
PROTECTOR
P_FAIL
DETECTOR
P_FAIL
DETECTOR
PRIMARY CIRCUIT
U20C04300
FULL
IGNITION
BRIDGE
CIRCUIT
Output voltage.
At the time of a start : 8KVp-p
At the time of stability : AC 60~129V
Output Frequency
CONTROL
■ When the output volt-
age reaches abnor-
mal voltage (exceeds
AC 130V), unit lamp
ballast will be shut
down and a lamp
signal
monitor
changes from L to H.
CPU : ---- Lamp monitor operation ----
DC OUTPUT
DC380~400V
DC OUTPUT
DC380~400V
LAMP
ASS'Y_3
: 50 Hz typ.
signal
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