Attempting to repair

[Ignitor]

Hello
This little circuit is expensive so I'm thinking if I get lucky and maybe fix this.
Could someone id the larger component?
Name ? ( IRL640S) thanks ,

 

[kellys_eye]

http://pdf1.alldatasheet.com/datasheet-pdf/view/135651/IRF/IRL640S.html

https://www.digikey.co.uk/products/en?keywords=irl640s

What makes you think it's defective?

 

[Ignitor]

Just guessing,the part doesn't work and has a history of a short life.would there be a way of testing it? I ordered one, just$1.93, thanks for your help

 

[kellys_eye]

Since you've bought the part, testing by substitution is as easy as anything else.....