PT-TX400, PT-TX310, PT-TW340, PT-TX210, PT-TW250 (serv.man3) - Panasonic Projector Service Manual (repair manual). Page 61

-   When all of LED indicators are off, the symptom indicates that the primary power supply circuit does not 

operate properly. Check the power primary circuit and parts as follows;

    

1. AC cord, F2001A/B (Fuse), filter board, POWER board, thermal switch.

   

2. The thermal switch opens when the surrounding temperature exceeds 120°C.

This projector provides a function which can be specified a defective area simply by indicating the LEDs/ Connect 
the AC cord and press 

 button once and then check the LED indication. 

-   When the WARNING (orange) and POWER (orange) 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 IC1002/IC1003 on the MAIN board and IC1902 of the 

temperature control board. 

-   When the WARNING indicator lights orange, 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.

When the abnormality occurs inside the projector, the P_FAIL signal (Error: L), FAN_ERR signal (Error: L), 
signal (Error:L) are sent to IC1001. And IC1001 sends the shutdown signal LAMP_DC_ON to the power supply 
circuit and the secondary power supply will be cut off and signal, viaIC3100 and P3002<lamp cover switch>, 
LAMP_ENto the lamp POWER board to cut off the power supply.

  An abnormality occurs on the secondary power supply;

   

Check the S16V check signal. P_FAIL signal becomes low when the abnormality occurs. 

  An abnormality occurs on the fan control circuit;

  

 If fans FN3001, FN3002, FN3003, FN3004 or FN3005 has an error, the FAN_ERR and P_FAIL signal 
become "L". 

  

 If the FAN_ERR signal becomes "L", the FAN_ERR signal will cut off the LAMP_EN signal provided for 
the lamp power 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 (KW10). 

Lamp cover switch (KW10)