PT-VX500U, PT-VX500E, PT-VX500EA, PT-VW430U, PT-VW430E, PT-VW430EA - Panasonic Projector Service Manual (repair manual). Page 7

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The lamp cover switch (SW901) cuts off the drive signal to the lamp 
circuit when the lamp cover is removed or not closed completely. 
After opening the lamp cover for replacing the lamp assy, place the 
lamp cover correctly otherwise the projector can not turn on.

There is a thermal fuse (SW902) inside of the projector to detect the 
internal temperature rising abnormally. When the internal tempera-

ture around lamp reaches near 113˚C, the thermal fuse will open to 
cut off the power supply to the lamp power circuit.
If  the  thermal  fuse  opens,  the  projector  cannot  turn  on.  Thermal 
fuse replacement is required. 

This projector provides the following circuit protections to operate in safety. If the abnormality occurs inside the pro-
jector, it will automatically turn off by operating one of the following protection circuits.

Fuse
(F601)

A  fuse  is  located  inside  of  the  projector.  When  the  ON(G)/

STANDBY(R)  indicator  is  not  lighting,  the  fuse  may  be  opened. 
Check the fuse as following steps.
The fuse should be used with the following type;

or

How to replace the fuse
1.  The fuse is placed on the AC 1ST FILTER board. Remove the 

cabinet  top,  MAIN&AV  board  following  the  "Mechanical  Disas-
sembly" . 

2.  Take  the  fuse  off  ,  and  replace  the  old  one  with  the  specified 

type.

Thermal fuse 

(SW902)

Lamp cover switch 
(SW901)