No Power - Sanyo PLC-XU350A Service Manual

Troubleshooting

No Power

This projector provides a function which can be specified a defective area simply by indicating the LEDs. Connect the
AC cord and press the Power button once and then check the LED indication.
- When all of led indicators are not lighting, the symptom indicates that the primary power supply circuit does
not operate properly. Check the power primary circuit and parts as follow;
AC cord, F601 (Fuse), Power board,
SW90 (Thermal sw.)
- When the WArNING (red) and PoWer (red) indicators are flashing, the symptom indicates that the projec-
tor detected an abnormal temperature risen inside the projector. Check the air filters and remove the object near
the intake and exhaust fan openings, and wait until the POWER indicator stops flashing, and then try to turn on
the projector.
The internal temperature is monitored by sensor ICs, IC8831, IC881 on the Main board and IC8811 on the
R/C board.
- When the WArNING indicator lights red, the symptom indicates that the projector detected an abnormality in
the cooling fan operation or in the power supply secondary circuits. Check fan operation and power supply lines,
and the driving signal status.
The P_FAIL signal (Error: L) is sent to pin 15 of IC301<SYSTEM CONTROL> and P_FAIL_LAN is sent to pin 370
of IC301<SYSTEM CONTROL> when the abnormality occurred inside the projector, and then the IC301 sends
the shutdown signal, LAMP_DC_ON, to the power supply circuit to stop its operation, and signal LAMP_SCI to
the lamp ballast board via IC4891 and SW901<lamp cover switch> to stop operation of the lamp circuit.
An abnormality occurs on the secondary power supply;
Check power supplies S16V, S6V, S-7V. P_FAIL,P_FAIL_LAN signal becomes "Low" when the abnormality
occurs on any of the power supply lines.
An abnormality occurs on the fan control circuit;
Check FN901, FN90, FN903, FN904, FN905, FN906 and peripheral circuit.
If any of the fans has an error, the fan lock signal drives Q3601 becomes "High". As the result, signal
FAN_ERR becomes Low and is sent to lamp ballast board to stop lamp circuit.
An abnormality occurs on the drive signals;
ON_15V signal (Power-on: H) is output from pin 01 of IC301 and switches IC59,15.5VL supply circuit,
ON_5V signal (Power-on: H) is output from pin 110 of IC301 and switches IC554,IC5081, 11-AMP supply
circuit, ON_3.3V signal (Power-on: H) is output from pin 11 of IC301 and switches IC561, 1.0V and Q358
3.3V supply circuit.
LAMP_DC_ON signal (Power-on: H) is output from pin 89 of IC301 and supplied to the P .C Control IC,
IC61, on the power supply board through Q651, and PC661.
LAMP_SCI signal (Power-on: H) is output from pin 14 of IC9885 and applied to pin  of IC4891 and output
pin 4 and then supplied to the lamp ballast board through SW901<Lamp Cover SW>.
LAMP_DET signal at the pin 85 of IC301 is applied from the lamp ballast unit. If the abnormality occurred
on the lamp ballast unit, LAMP_DET signal becomes "High" and then IC301 shuts down the power supply
circuit.
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).
short in normal
SW90 opens when the surrounding temperature of the switch exceeds 100°C.
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