Query to find distinct record

This should be easy.
I have a SQL table with the data as follows:

Part#     Rev     Status
P123       A          O
P123       B          A
P123       C          O
P123       D          O
P124       C          A
P127       A          O
P128       A          O
P128       B          A
P129       F           O
P130       F           A
P134       A           O
P134       B           O
A=Active Part
O=Obsolete Part

I need to write a query that only pulls the part numbers that are obsolete (no active status regardless of rev).

The correct results would be
P127
P129
P134