Ken there is one question i would like to ask.
You said the CMOS was drity, well this is not really possible, after manufacture as the front filter is there to protect the CMOS.
However if you remove the front filter, and do not cover the CMOS, or place it into a new sipped sandwich bag, or leave it open it will get dust.
Ken i have done 3 5d's, exactly to what you have done, there is no chance of dust or any other particles of dirt getting into the CMOS unless you left it exposed after removal.
So I wonder why yours was so dirty as you said
Leon
