Last time I bought Sony repair parts I got them directly from Sony, but I just looked and it seems like they stopped selling them directly. They appear to be using a couple of distributors, according to this:
https://sonystyle.custhelp.com/cgi-b...p?p_faqid=5772
I'd start with the Sony number first, then the distributors.
See if you can get a repair manual, then you'll have a parts number, which greatly simplifies the process of ordering.