projector compaq mp2810 fuse/viper/PC817 blows

[caramp]

i replaced
SFH617A with PC817 ,
viper100A with viper100A,
capacitor 53uF 63V with 100uF 63V

default main fuse is T2.5A, i try 2A and it blow.

T2.5A will not burn out, but viper explodes!!

without viper pcb nothing is occurs

projector has been tested without lamp.

projector image

viper pcb

bottom pcb

 

[(*steve*)]

A transistor exploding like that (especially repeatedly) tells me that you may have a dead short somewhere. The fault is obviously causing massive overload to that poor transistor.

I presume this is the power supply. It looks like it receives rectified mains (400V) and produces several output voltages.

Does the transistor explode if the unit is powered on but the load is not connected?

If not, try measuring the resistance (with the power supply removed) across the unit's rails. So measure the resistance wherever this connects (low voltage side) between each voltage and ground. Are any of them really low? (like near zero)