Control Panel Button Problem – HP Laserjet 4000, 4050, 4100 Printer
Control Panel Button Problem – HP Laserjet 4000, 4050, 4100 Printer
I can’t believe I haven’t found more info on the net about the control panel button problem with the HP laserjet 4000, 4050, and 4100 printers. I looked everywhere on the web and nobody seems to be talking about this issue. Maybe because most people just replace the control panel. Ever since these machines were a few years old I was taking apart the control panels and cleaning out the contacts to make them work better or I should say, the way they should. In this article I would like to talk about what happens and how to go about fixing this simple control panel button problem.
Troubleshooting the Control Panel Button Problem in the HP Laserjet 4000, 4050 and 4100.
Not very hard. You go to press the buttons and majority of them don’t work or if they do you have to hold them done and move them around a little before it moves on to the next menu setting. When I Â work on any machine the first thing I do is go into the information menu and print of a configuration page. In order to do this on the HP 4000, 4050, and 4100 printers you have to press the menu, value, and select buttons. Majority of the time it goes into the menu structure but when I press the value > it doesn’t work. However the < value button works. At that point I usually check the other buttons and most the time only half or so work correctly. Typically, I make a mental note to fix the control panel button problem later and move on to the actual problem I was called on. For some reason, probably because the machines work so great, nobody ever calls me for this issue but more than half the machines I work on the control panel doesn’t work.
Control Panel Removal Procedure
Control Panel Overlay
1. Using a flat-blade screwdriver, gently pry upward on the right side of the Control Panel Overlay to loosen it.
2. Remove the Control Panel Overlay from the tabs on the left and lift it upward, off of the printer.
Not All Control Panels Look the Same
Control Panel
1. Using a flat-blade screwdriver, pry each side of the Control Panel upward.
2. Remove the top of the Control Panel from the tab.
3. Disconnect the ribbon cable from the Control Panel.
Control Panel Button Disassembly
1. Flip control panel over so and disconnect the white flex cable from the keypad PCA
2. Unscrew the 1 regular screw securing the metal leaf spring in the middle and the  5 or  6 tiny gold or black screws securing the keypad to the plastic.
3. Lift the keypad up and set aside. Beneath the keypad is a clear mylar plastic piece with metal contacts the correspond with the buttons.
4. If you look closely half  the metal contact is held on with the mylar and the other half is exposed. The back side is totally coated by the mylar. The metal exposed has a coating on it that prevents the metal beneath from making contact with the Keypad PCA. Take a screwdriver and scratch the coating away slightly.  Don’t over think this. Its like scratching off a lottery ticket and it doesn’t take hardly any force at all. Just a gentle scratch to remove the top layer and it doesn’t have to be perfect. I usually just scratch  each contact for 2 or 3 seconds then move on to the next. Easy to tell if you’re doing it right because you will see the shiny metal underneath once you start scratching. Once you’ve done all the contacts reinstall and your good to go.
Conclusion About the Control Panel Button Problem on the HP Laserjet 4000, 4050, and 4100 Printer
Hopefully this article has helped you solve your control panel button problem. This problem should be easy to resolve with a little work. Like I said earlier, I can’t believe I haven’t seen more topics related to this issue given just about everyone I work on exhibits this problem. While I mainly see the control panel problem on the 4000 and 4050 printers I included the 4100 because I’ve ran into a few times on this model.
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