Canon LV-X4U Service Manual page 65

• An abnormality occurs on power starter signals (ON_5VA, ON_3.3V, ON_15V,
LAMPDC_ON, DC_ON);
LAMDC_ON signal (Power-on:H) is output from pin 15 of IC1803 and applied
to PC643 on the Power Board. It drives the power oscillation circuit and
power supply in the Power Board.
DC_ON signal (Power-on:H) is output from pin 16 of IC1803 and switches
Q661<15.5V> on/off.
ON_15V signal (Power-on:H) is output from pin 72 of IC301 and sent to
Q2501, then 15VL line is supplied.
ON_5VA signal (Power-on:H) is output from pin 71 of IC301 and sent to
IC5081 and Q3582 to switch power supply 5V_AUDIO and 5VA.
When an abnormality occurs on Lamp drive circuit.
• LAMP_POW signal (Power-on:H) is output from pin 140 of IC301 and sent to
IC4811 via IC4852.
SCEL signal (Lamp-on:L) is output from pin 7 of IC4811 via IC4801 and sent to
Lamp Ballast Unit through SW901(Lamp Cover SW).
• TXL signal is output from pin 12 of IC4811 and sent to Lamp ballast Unit via
IC4801.
(TXL signal is applied for lamp power control. Lo: Low power, Hi: High power)
• RXL signal (Lamp status signal) is output from Lamp Ballast Unit and sent to pin
9 of IC4811 via IC4801, then LAMP_ERR signal is output from pin 3 of IC4811
and sent to IC301 via IC1811.
If an abnormality occurs on the lamp ballast unit, RXL signal and LAMP_ERR
signal become "H" and then the projector will be cooled down and to stand-by
mode (POWER indicator lights red.).
[Lamp cover switch]
Make sure that the lamp cover is mounted correctly. If not or the lamp cover removed,
the lamp does not light on for the safety. Check the lamp cover and lamp cover switch
(SW901).
Fig. 4-1
4-3
Part 4: Troubleshooting