Lamp Abnormality - Sanyo PLV-WF20 Service Manual

Troubleshooting

Lamp Abnormality

■ The Lamp Driving Circuit (
THERMAL SWITCHES
LAMP COVER
SW
SW902 SW903
K88D K88C K88B
LAMP FANNET
K88A
3 1
K8U
12VA
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 90ºC, the
temperature switches open and 12V is not supplied to PFC1-2 board, also the
Power fail signal "PF_TH" bocomes "Low".
SW903 - SW904 -- 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_1 )
example
SW904
AC INPUT
AC85~264V
3 3
PF_PFCFAN2 (n/a)
K8Q
5 5
FAN12V
4 4
12V
6 6
LAMP3
7 7
LAMP4
1 1
PF_PFC3
2 2
PF_PFC4
8 8
GND
DC INPUT
DC380~400V
1 1
LAMP3_RX
2 2
GND
3 3
S5V
4 4
BLAST_SW3
5 5
LAMP3_TX
PFC1-2
LINE
FILTER
CN6
H : ON
H : ON
L : Abnormality
L : Abnormality
BALLAST1
FILTER DOWN
BUFFER CONVERTER
CN2
H : Abnormality
H : ON
■ When the temperature
around a lamp driver
reaches 85 degrees,
unit lamp ballast will
be shut down and a
lamp monitor signal
changes from L to H .
■ The CPU performs an input check by the lamp monitor
pin (LAMP_RX).
■ When the "H" signal continues 1 second or more con-
tinuously, the CPU judges the state to be abnormal.
■ 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.
-133-
BRIDGE ACTIVE
DIODE FILTER
THERMAL
PROTECTOR
BRIDGE ACTIVE
DIODE FILTER
THERMAL
PROTECTOR
P_FAIL
DETECTOR
P_FAIL
DETECTOR
PRIMARY CIRCUIT
FULL IGNITION
BRIDGE CIRCUIT
Output voltage.
No load Voltage Range : DC180 ~ 210V
At Lamp Lighting stability Range: AC 77 ~ 150V
CONTROL Output Power.
Rated Power Range
Reduced Power Range : 264 ~325.6 9W
■ When the output volt-
age reaches abnormal
voltage (exceeds AC
130V ), lamp ballast
board will be shut down
and a lamp monitor sig-
nal changes from L to H.
CPU : ---- Lamp monitor operation ----
DC OUTPUT
DC380~400V
DC OUTPUT
DC380~400V
LAMP1
: 330 9W