Temperature Abnormality - Sanyo PLC-HF15000L Service Manual

Troubleshooting

Temperature abnormality

■ temperature monitor operation
The temperature monitor system is provided to prevents damage of optical com-
ponents (the LCD panel and polarization film etc.) inside a projector from over-
heat. Two protection systems are provided. Each system operation as follows :
the temperature monitor -1:
● to control the air-flow of the cooling fans.
The CPU checks the temperature and atmospheric pressure inside a projector.
It checks a temperature using temperature sensors IC8811 and IC8851, and it
checks an atmospheric pressure using pressure sensor-IC886. The CPU judges
data from sensors and controls the air flow of the cooling fans so the temperature
inside the projector is maintained to normal temperature.
● to shut down the projector urgently.
The IC301 checks temperature of LCD panel periphery (IC8851) and intake air
(IC8811). If each part temperature reaches abnormal temperature, the CPU will
turn off the projector, and will blink WARNING TEMP. indicator. Cooling fans
operate until temperature returns to normal.
the temperature monitor -2 :
● temperature check of lamps :
Temperature switches (SW903, SW904 for Lamp1 and Lamp, SW905, SW906
for Lamp3 and Lamp4) are placed near the lamps. Temperature switches will op-
erate, if temperature reaches 90ºC. When temperature switches become open,
they cut off 1V line supplied to PFC1& boards, after that the projector will shut
down, and indicates the error on the projector with the LED indicators ( LAMP
indicator : On, other indicators: blinking).
■ Sensor's operation
The sensor's operation is as follows:
IC886 : For FAN control
IC8851 : Inside air temperature monitor (Panel)
IC8811 : Inside air temperature monitor (Room)
■ Led indicators
When the internal temp rises, the WARNING TEMP. indicator will start blinking.
When the temperature around the Lamp1, ,3 or 4 rises abnormally , the LAMP
indicator is lighting and other indicators are blinking.
-174-