My D-500 will kick out roughly 30-40 PSI Ive only seen it hit 40 twice, Now I dont know what the exact rating is......but Ive heard everywhere from 20-40....
Glad you got the problem solved though. You'll want to pick up an airtank for it, though to help smooth out the airflow from the diaphram(sorry Mike didnt mean to steal your info LOL). MikeV told me I would need one, and I thought NAH, mine doesnt pulse....well what happened was I just didnt notice it until I was wrapping up a paint job spraying really thin paints at low PSI, thats when I noticed it! DOH!!!!!! I will pick up my airtank tomorrow, it was in today but I didnt have a chance to make it by there.
To find out more info about what Im reffering to you can check this thread out :
http://www.finescale.com/fsm/community/forum/topic.asp?TOPIC_ID=13075
Hope this helps.