Digital BW, The Print

After taking apart my 9500 for cleaning and to resolve an ink 
problem, I now have a new problem.

If I load any kind of roll paper, after hitting pause, the printer's 
paper setting switches itself from roll to "sheet". Does not matter 
what i have selected in driver, or what type of paper. After printing, 
the printer will spool out yards of paper, looking for the end of the 
sheet.

I was printing on rolls of canvas no problem, rolls of EEM no 
problem, cutter on or off. Now it always switches to "sheet".

Maybe I knocked the paper thickness sensor out of whack? Or 
one of the sensors is dead or dirty? Or do you think the main 
board is going bad?

Any ideas? Any one ever adjust or replace a paper sensor?

thanks,
dan smith