Scanner prints just black sheet
The mystery is solved!!
I live in Norway and my CanoScan 5000F has worked brilliantly until it suddenly started to display a black preview in ScanGear, black scanning and to no surprise,- a completely black printout.
My first thought was that the scanner-lamp had died,- but that was strange because I hadn't used the scanner that much. I hadn't made any changes to my computer system either. The operating system (Windows XP), scanner software and drivers were exactly as before.
I made a new testrun and saw the light come on from the side of the scanner and move along the platen as usual. The sound and operation of the scanner seemed to be all normal.
A quick check on the internet revealed that there were many other guys out there who had experienced the same problem. Some had tried new drivers, uninstalled and reinstalled, but to no luck. I also tried the same method, but was stuck with the same problem.
I have a background as an electronic service-engineer, and this mystery really gave me a good challenge. Why did so many people experience the same thing? Why couldn't Canon answer and give a reasonable explanation to the phenomenon? What was the common factor in all these cases?
Every scanner is connected to the mains via a power-unit. Mine is European standard with type nr. PA-08E. It is labelled with output DC 12V (stabilized!) and a rated current of 1.25 A at this voltage.
I brought the power-unit to my lab for a test. When I measured the voltage without any load (no scanner connected) it read 12 V as stated,- so it seemed to be ok.
But when I connected a load (a car light bulb 12 V / 3 W - equivalent to a current of just 0.25 A), the lamp just barely glowed and the voltage (that should be 12 V constantly) dropped to just 4 V.
This proved without any doubt that the power-unit was defect. It could no longer maintain a constant 12 V during load.
I had a variable power-supply in my lab that could be set to 12 V and connected to the scanner for a test. But Canon had made a very peculiar connection to the scanner by using a rare male power plug (with a center (+) pin inside). Normally a round hollow (female) plug is used on such power-units.
So I cut the DC cable a few centimeters from the power-unit, split the two leads 4 cm apart and dismantled 1 cm of insulation from each end. On my power-unit one of the leads were marked all the way with text, and this one proved to be the minus (-) lead connected to the outer (metal) part of the DC plug.
The two ends were connected to my power-supply (with correct polarity!), and the other end with the DC plug were connected to the scanner. Power-supply was switched on and my computer system was restarted.
I opened the Paint Shop Pro program, clicked 'Twain Acquire' and the ScanGear CS window appeared.
After this insident a calibration of the scanner is required: Close the lid with no document inside, click 'Advanced Mode >>' down right and then 'Settings' / 'Quality' / 'Calibration'. The scanner will do some adjustments for a few seconds and finish when the small calibration window close.
At last my CanoScan 5000F came back to life again. The preview was normal, and the scanned images as superb as they had been before.
Conclusion: Do not throw your scanner away! Buy a new power-unit with DC 12 V stabilized and at least 1.25 A. Brand is not important as long as it is of good quality and correct voltage/current, but cut and use the cable and plug from the defect power-unit as I described earlier. Remember to isolate the connecting area (+ and -) firmly.
Regards Tore Nilsen
Nov 22, 2008 |
Canon CanoScan 5000F Flatbed Scanner