Round disk under the inspection plate like this one:
{
http://www.shop.sew-classic.com/Sing...nes-SCE428.htm }
~ OR ~
The tab with screw type:
{
http://www.shop.sew-classic.com/Ligh...ack-SCE503.htm }
Of the top of my head I think most of mine have the first type. But I have to dig them all out to make sure what they have.
I just acquired one that came without a light. So I'm mulling over which type to get.
Joe