string not equal query, postgresql 9.4.4

Hi all,

Having a bit of a head-scratching problem. I'm writing a query where I want to output only distinct rows where one
char(4)field does not equal a specific value. Something like: 

select distinct testname where result <> 'PASS";      #i.e., only the FAIL or WARN tests

I've tried several different variants like "!~", "not like ('PASS')", "is distinct from 'PASS'", and so forth, but
obviouslyI'm missing something as every row is being output not 
just the ones which do not equal PASS. What would be the correct syntax for this in a 9.4.4 database?
--
Jay