I tried to find the part, still no luck.
I was wondering if any one can help me.
I like to know the PSU PWM chip no.

 

I tried to find the part, still no luck.
I was wondering if any one can help me.
I like to know the PSU PWM chip no.

Unless you found the chunk of casing with the number on it - and its still readable, your best hope is a look inside one that hasn't blown up.

You could search for a service manual and hope one turns up.

 

No chunk available.
I have to search for the manual

 

No chunk available.
I have to search for the manual

If that includes a schematic and parts list you're nearly there.

But those chips are pretty reliable, so chances are something caused that. The first thing I'd look for is any small electrolytics near the chip, they don't usually bulge or concave the top of the aluminium can when they've had it. In most cases the chip will have some sort of power on start up arrangement, once the PSU is running the chip gets its Vcc from an extra winding on the transformer - sometimes this rectified and (hopefully) smoothed rail is also sensed for the error voltage.

These chips usually have overcurrent shut down, but a shorted secondary side rectifier can sometimes blow the chip.