Vertical big black line when scanning, both color or B&W.Not in the middle but on the right side. It is Canonscan LIDE 500F. What is the solution?

Only two possibilities---- check out 1 by 1.
1)the scanner glass is dirty .or a hair like material is got stuck up on that particular side.so clean the scanner glass assembly from the upper side with a dry and clean cotton cloth.and then check out.if that works then the problem was dust.but if that does not works then .

2)in the scanner glass under it there is a assembly that moves ,that moving assembly is called scanner assembly.that scanner assembly has a thin tubelight fitted in it.that tube light is controlled by a small chip circuit .which is in that moving scanner assembly under the glass.that circuit is faulty.that circuit has ten points .if any of the one point is faulty at that particular portion the tubelight will not glow and the line will appear on each scanned document.
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TO SOLVE THIOS PROBLEM
the small chip curcit in the scanner assembly has to be replaced.the cost of that chip circuit is $23 .
a local printer reparing engineer will be helpfull for opening the printers scanner assembly and fitting the chip circuit.

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