No Power - Panasonic PT-TW230U 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
- 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 fuse exceeds 94°C.
- When the WARNING (red) and ON(G)/STANDBY(R) (red) indicators are flashing, the symptom indicates that
the projector detected an abnormal temperature risen inside the projector. Check the air filter and remove the
object near the intake and exhaust fan openings, and wait until the ON(G)/STANDBY(R) indicator stops flashing,
and then try to turn on the projector.
The internal temperature is monitored by sensor ICs, IC8821 on the main board and IC8811 on the temp sersor
A board,IC8831 on the temp sersor 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 215 of IC301 <SCALER>, 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 the signal LAMP_SCI output from IC9885<SUB CPU> is sent to the lamp ballast board via
IC4891<NAND> and SW901<lamp cover switch> to stop operation of the lamp circuit. LAMP_DET signal at the
pin 285 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.
An abnormality occurs on the secondary power supply;
Check power supplies S16V, 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, FN907 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 circuitt.
An abnormality occurs on the driving signals;
The table below shows the driving signal of each power supply.
Driving signal
ON_50V
ON_150V
ON_33V
ON_16V
POWER_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).
button once and then check the LED indication.
IC output Pin No.
419
95
IC301
188
96
IC9885 5
I/O Level Swich/IC
O H IC5549
O H IC592
IC5621
O H
O3582
O H Q5701
IC2391
Q5830
O H IC5861
IC5602
RL601
-63-
Power/Circuit
12V
15.5V_PNL
1.0V
3.3V
S-5V
S5V
SS3.3V
S1.8V
S5V
Standby circuit
SW901