How can I clean the contact for the keys, some are hard to push?

1: Clear an area on a table or other large flat surface.
2: Spread out a towel or a padded cloth.
3: Place your Q-chord on the towel upside down with the battery compartment facing you.
3: Remove the batteries. Unscrew all the screws. You don't have to remove them. Leaving the in the case means you won't lose any
4: Lift the bottom case off carefully. There's a white connector that plugs into the bottom printed circuit board. Gently uplug the connector and set the bottom of the case aside screw side up so the do nor fall out.
5:There are four ribbon cables. One at the portal for the q-cards and three others. Gently unplug them from the circuit boards.. Don't worry, you can't get them mixed up

6: Unscrew all the screws for the top green circuit board and remove it. Set it aside.

7: You will see a tan board under it that slides partially under a smaller green board. Don't bother the smaller circuit board. Unscrew all the screws in the tan board, and set them aside.

8: Lift out the tan board and flip it over. You can use contact cleaner, or a little rubbing alcohol Q-tip to clean the contacts. Or use a lead pencil eraser and gently "erase" over the contacts. A little bit will usually do you. Don't overdo ANYTHING.

9: Reassemble in reverse procedure. Don't worry. The parts will only go back on the right way. Once you're done, power it up and try those bad chord keys again. They should work.