Beko 3731 dishwasher - clean bottom, dirty top!?

My dishwhaser (3 yr old) has started to spray and weld a green scum on glasses and cups in the top tray. Plates, cultery, pans etc in the lower tray are cleaned without any problem. Have taken the pipe feeds and water jets off, cleaned and replaced, tried a variety of salt/tablets/rinse aid products but still no resolution. Any ideas appreciated.
Dirty Bleeder, May 2005


done
The answer after everything was to get a new upper spray arm - a plastic washer has broken and this was the cause

Dirty Bleeder, May 2005
use a couple cups of white vinegar and run it through until the green slim deposits are gone.

underthetornado@yahoo.com, May 2005
link Click here to see other fixes for Beko.