Sanyo PLC-SU25, Service Manual

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Troubleshooting
No Power
Reset switch
The microprocessor inside the projector may occasionally
malfunction and does not allow any controls. In this case,
press the reset switch on the rear panel with a sharp tool to
restart the projector.
- When all the 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)
Line filter board
SW902 (Thermal sw.) ......short in normal
SW902 opens when the surrounding temperature of the switch exceeds 100°C.
SW904 (Interlock sw.) ......short in normal
Check the lamp cover is fixed firmly. The projector cannot turn on with lamp cover removal.
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 the WARNING TEMP indicator (red) is 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 WARNING TEMP indicator flashing stops, and then try to turn on the
projector.
The internal temperature is monitored by sensor ICs, IC4801 on the Temp board and IC8801 on the Main board.
- When both of the TEMP WARNING (red) and READY (green) indicators are flashing at the same time ,
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.
An abnormality occurs on the secondary power supply;
Check power supplies 15.5V, 6VS, 5VS, -5V. PF_LAMPDOWN signal (Error: L) is sent to pin 79 of
IC301when the power error occurs.PF_LAMPDOWN signal is output from pin 3 of IC711 driven by
POWER_FAIL (Error:L) signal on pin 2. When IC301, system control, detect s“L” on pin 79, IC301 sets the
projector into the standby mode and indicates error mode with the LEDs flashing.
An abnormality occurs on the fans operation;
Check FN901, FN902, FN903, FN904, FN905, FN906.
An abnormality occurs on the power failure detection circuit;
Check Q69A, Q68P, Q87P, D68P, D67P on the power board, IC711, and Q722 on the Main board.
An abnormality occurs on the drive signals;
5V_SW signal (Power-on: H) is output from pin 146 of IC301 to Q661, IC65A through Q301 on the Main
board and Q662, Q65B and Q65C on the Power board.
FANDRIVE signal (Power-on: H) is output from pin 14 of IC1804 to IC671 and IC681 through Q672 and
Q682 on the Power board.
LAMP-BST-SW signal (Power-on: H) is output from pin 15 of IC1813 to IC611 on the P.F. board through
Q651 and PC643 on the Power board.
LAMP_POW signal (Power-on: L) is output from pin 2 of IC301 to lamp ballast board through the lamp
switch circuit, IC711, IC721 and IC731.
- When the POWER indicator (red) is lighting, the
symptom indicates that the projector detected an
abnormality in the circuit but is not specified error.
Check the following;
Lamp cannot turn on, check following signals;
LAMP_ERR signal (Error: H) is sent from the
lamp ballast board and input to pin 8 of IC1822.
LAMP_POW signal (Power-on: L) is output from
pin 2 of IC301 to lamp ballast board through the
lamp switch circuit, IC711, IC721 and IC731.