Question about Brother MFC-9420CN All-In-One Laser Printer
Wont print because it insists that the back cover is open. Used to have to squeeze the back cover until you could hear it "catch", now it won't even catch and I can't tell where the sensor is.
The "sensor" is a simple switch, that is built into the printers backside, on the left hand side (seen from the front). A small plastic pin, that is screwed into the back cover, pushes this switch, when the cover is closed, but ...
The back cover mechanism is designed very poorly. The locking mechanism is on the opposit side of the printer. So cover is not held in position anywhere close to the sensor. This is causing the switch to "flicker" or to become "open" during operation.
Quick and dirty fix:
1) Ask you wife for one of these plastic kitchen sponges.
Any plastic sponge with a height of 6 to 8 cm (3 to 3.5 inches) will be fine.
2) Open the back cover. Standing behind the printer, on the top right inside of the cover, there is a small white pin fastened with one screw. Losen that screw a bit, pull the pin out as far as possible (to make it as long as possible) and fasten the screw again.
3) Close the back cover
4) Take the (dry !) kitchen sponge and push it into the gap between the top of the back cover and the bottom of the flatbed scanner. Still looking at the printer from the backside, it has to be in the right 30 percent of the cover. The sponge gives enough pressure to hold the cover down just a bit and this is the trick to solve that issue dirty but permanently ...
Posted on Mar 29, 2008
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