Can you tell us what the brand name is? I believe you're talking about a Cuisinart but they don't make a 660, they make a 600. If you come back and tell us the brand name I may be able to help more.
In the meantime, take a look at this manual and see if looks like your cooker: http://www.hippressurecooking.com/cuisinart-electric-pressure-cooker-manual-cpc-600/
Answers & Comments
Can you tell us what the brand name is? I believe you're talking about a Cuisinart but they don't make a 660, they make a 600. If you come back and tell us the brand name I may be able to help more.
In the meantime, take a look at this manual and see if looks like your cooker:
http://www.hippressurecooking.com/cuisinart-electric-pressure-cooker-manual-cpc-600/