Lamp Abnormality - Sanyo PLC-HF15000L Service Manual

Troubleshooting

Lamp abnormality

■ Lamps
- 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.
■ Lamp cover Switches
Make sure that the lamp cover is mounted correctly. If not , the lamp does
not light for safety.
Check the stay of the lamp cover and the lamp cover switches.
SW77A and SW77B detect for Lamp 1
SW77C and SW77D detect for Lamp 
SW77E and SW77F detect for Lamp 3
SW77G and SW77H detect for Lamp4
Switches -- open : Lamp cover is opened
■ temperature Switches
When the internal temperature near the lamps reaches near 90ºC, the tem-
perature switches open and 1V is not supplied to PFC board.
SW903 - SW904 for Lamp 1 and  -- open : Abnormality
SW905 - SW906 for Lamp 3 and 4 -- open : Abnormality
■ Led status
LAMP rePLAce Indicator
- When the LAMP REPLACE indicator lights:
Any of the projection lamps is approaching its end
- When the LAMP REPLACE indicator flashes:
The lamp reached its end.
LAMP 1/2/3/4 rePLAce Indicators
- When any of the LAMP 1//3/4 REPLACE indicators lights:
The corresponding lamp is approaching its end.
- When any of the LAMP 1//3/4 REPLACE indicators flashes:
The corresponding lamp needs to be replaced
■ Lamp monitoring
- The CPU performs an input check by each lamp monitor signal (LAMP_
RX).
- When the lamp monitor signal becomes "H" for 1 second or more, the
CPU judges the state to be abnormal on its lamp.
- When the CPU detects abnormal condition, the CPU only turns off a lamp
which has an abnormality and the CPU uses another remaining lamp to
keep the projector on.
Check that the lamp on/off signals
(BALAST1_SW,
BALAST3_SW,
are correct.
Check that the lamp power drive
signals (PFC1_SW, PFC_SW,
PFC3_SW, PFC4_SW) are cor-
rect.
Power-On: H
If the Lamp ID board is not mount-
ed firmly, the warning message will
appear on the screen and some of
the functions may be disabled.
-175-
BALAST_SW,
BALAST4_SW)
Lamp-On: 3V, Off: 5V