Troubleshooting; No Power - Sanyo PLC-XU58 Service Manual

■ Troubleshooting

No Power

This projector provides a function which can be specified a defective area simply by indicating the LEDs on the con-
trol panel. 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
SW902 (Thermal sw.) ......short in normal
SW902 opens when the surrounding temperature of the switch exceeds 90°C.
- 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, IC2801, IC2831 and IC2861 on the Main 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 48 of IC801<SUB CPU> when the abnormality occurred inside the projector,
and then the IC801 sends the shut down signals, 5V_SW and LAMP_BST_SW, to the power supply circuit to stop the
operation.
An abnormality occurs on the secondary power supply;
Check power supplies 15.5V, S15.5V, S6V, S-5V. P_FAIL signal becomes "Low" when the abnormality occurs on any of
the power supply lines.
An abnormality occurs on the fan control circuit;
Check FN901, FN902, FN903, FN904, FN905, FN906 and peripheral circuit.
Check Q67P, D67P, Q68P, D68P and peripheral circuit (Over voltage detection circuit).
An abnormality occurs on the drive signals;
POWER_SW signal (Power-on: H) is output from pin 1 of IC801 and input to pin 17 of IC1881, and output from pin 3 by
the name of 5V_SW.
LAMP_BALAST_SW1(Power-on: H) is output from pin 12 of IC1851(D/A) and supplied to the P.F Control IC, IC621,
through the IC1881, Q651, and PC643.
BALAST_AC signal (Power-on: H) is output from pin 39 of IC801 and input to pin 11 of IC1881, and output from pin 9 by
the name of BALAST_AC1. BALAST_AC1 signal is applied to pin 2 of IC4891,NAND, and output pin 4 and then supplied
to the lamp balast unit through the Lamp Cover switch(SW901).
CHO_RXD signal at the pin 77 of IC801 is applied from the lamp balast unit. If the abnormality occurred on the lamp bal-
ast unit, CHO_RXD(LAMP_DET) signal becomes "High" and then IC801 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).
Reset switch
The microprocessor inside the projector may occasionally
malfunction and does not accept any controls. In this case,
press the reset switch on the rear panel with a sharp tool to
restart the projector.
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