No Power - Panasonic PT-VX400U 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 ON/STAND-BY 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 fuse)
SW902 opens when the surrounding temperature of the switch exceeds 113°C.
- When the WARNING (red) and POWER (red) indicators are flashing, the symptom indicates that the projector
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, IC8821 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), FAN_ERR_B signal (Error: L), FAN_ERR_C (Error: H) are sent to pins, 215, 267,
and 29 of IC301 <SYSTEM CONTROL> respectively 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 SCIOUT to the lamp ballast board via IC9886 and SW901<lamp cover switch> to stop operation of the
lamp circuit.
An abnormality occurs on the secondary power supply;
Check power supplies S16.5V, S6V, S-7V. P_FAIL signal becomes Low when the abnormality occurs on
any of the power supply lines.
An abnormality occurs on the fan control circuit;
If fans FN901, FN902 or FN903 has an error, the FAN_ERR and P_FAIL signals become "L". If fans FN904
or FN905 has an error, the FAN_ERR, P_FAIL and FAN_ERR_B signals become "L". If fan FN906 has an
error, the FAN_ERR_C signal becomes "H".
The FAN_ERR signal cuts off the SCIOUT signal which is supplied to the lamp ballast board if the FAN_
ERR signal is "L".
An abnormality occurs on the drive signals;
ON_15V signal (Power-on: H) is output from pin 94 of IC301 and switches IC592,15.5VL supply circuit,
ON_3.3V signal (Power-on: H) is output from pin 93 of IC301 and switches IC5621 - 1.0V, IC3852 - 3.3V
supply circuits.
LAMP_DC_ON signal (Power-on: H) is output from pin 89 of IC301 and supplied to the PFC Control IC,
IC621, via PC661 on the power supply board. POWER_ON signal (Power-on: H) is output from pin 21 of
IC9885<SUB CPU> and supplied to the oscillator IC, IC631, via PC663 on the power board.
SCIOUT signal (Power-on: H) is output from pin 23 of IC9001 and applied to pin 2 of IC9886 and output pin
4 and then supplied to the lamp ballast board through SW901<Lamp Cover SW>.
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).
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