0 - 2 of 2 tags for working of case when then else in teradata

I've been working on this for hours!  Literally hours and I can't seem to get my statement to work.  I'm converting a decode statement. and I can get

one of them to work.  But I can't get them all to work the way they currently work in the Decode. 

 

Hi..
I am new to Teradata and really confused with the working of Case statement in Teradata.
Somebody please help me out.. :(

In my select clause,i have a case statement as
CASE
WHEN PROD.PROD_TYPE_CD=INSRNC_TYPE_CD_XREF.PROD_TYPE_CD AND
INSRNC_TYPE_CD_XREF.PROD_LVL_4_DESC='NA' AND
INSRNC_TYPE_CD_XREF.PROD_LVL_3_DESC='NA' AND
INSRNC_TYPE_CD_XREF.MBRSHP_SOR_CD='NA' AND
INSRNC_TYPE_CD_XREF.BNFT_PKG_ID='NA'