Lamp Abnormality - Sanyo PLC-UF15 Service Manual

System Control
I The lamp emits light through arc discharge. To initiate arc discharge, dielectric breakdown must
occur between the lamp electrodes. The high-voltage pulse generator generates and applies high-
voltage pulses with peak values of about 20kV between the lamp electrodes in order to generate
glow discharge. This in turn results in dielectric breakdown between the electrodes, causing a shift
from glow discharge to arc discharge.
I After projector turned on, 30 seconds are required until the light output stabilizes. After the projector
is turned off, the cooling fan operates for 90 seconds to cool down the lamp and reduce gas pres-
sure inside the lamp. During this "cooling down" period, the projector cannot be turned on.
Hot circuit
FUSE
F901
AC-INPUT
Isn't the lamp cover of a projec-
tor removed?
When it is removed, the projector
cannot be turned on.
Is the lamp cover attached correctly?
And has not the boss(Inner side of the
lamp cover) broken?
Check the boss and the Interlock switch
(SW902).
SW902 -- open : Abnormality
NOTE :
I The ready (green) LED indicates lamp monitor
operation as follows:
LED off: Lamp is being cooled.
LED on: Lamp is being lit or already cooled down.

LAMP ABNORMALITY -1

NOTE :
INTERLOCK SW
SW902
FANS
FANS
LAMP
REPLACE
WARNING
TEMP.
READY
LAMP
INDICATORS
I CPU performs an input check by the lamp monitor pin.
I When the "H" signal continues 1 second or more continu-
ously, CPU judges the state to be abnormal.
I When it has detected abnormal condition, CPU turns off a
projector compulsorily. And CPU sets up the cooling time for
90 seconds.
I The projector cannot be turned on during a cooling time.
Troubleshooting
ASS'Y POWER
DC out
16V /9V /6.25V /-6V
POWER
CONTROL
FAN
ON/OFF CONTROL
I / O
EXPANDER
SUB POWER
CPU : ---- Lamp monitor operation.----
-34-
AC
Always
DC out
SWITCH
Switched
CPU IC801
and
I / O
EXPANDER
IC1831