Fixing sticky keys, chassis alignment
Last weekend I had to pull my Forte out of its semi-permanent stand, at church, to change some cabling; trivial stuff. When I put the board back in, I noticed right away that several keys in the lower octave were now sticking -- I've never had a single mechanical or electrical issue before.
I pulled the board back out, flipped it over, and immediately noticed that 2 of the 3 screws that anchor the rear of the keybed to the chassis case were missing, and the third was hanging on by a thread (pun intended). My guess is that steady playing had rattled them all out over time, they fell out, and the cleaning people swept them up. The board never moves, so the (heavy) keybed was staying in place, although the rear of it was essentially floating free inside the case.
So, to get through rehearsal, I retightened the one remaining keybed screw which helped a little, but not that much; struggled for an hour with random left-hand keys sticking down. Took the board home to work on it, stopped by HomeDepot on the way to buy some (metric) replacement screws, and refilled the two empty screw holes. That fixed almost all the sticking keys, but the "fixed" ones were still making an uncharacteristic clack sound when they bottomed out. OK, time to open up the case.
The Forte turned out to be quite easy to open up and work on, without having to unplug any ribbon cables or worry about loosing any nuts inside when unscrewing from the outside. Remove the endcaps (hex screws), then about 20 identical screws around the underside perimeter, plus the three rear keybed screws in an underside, centrally-indented channel. The control panel then flips straight up and back; no hinges, but you can just lay it upside down behind the main case with all the cables still plugged in; no sweat.
Finally, here's the important bit I wanted to document for the Forte owners. If you lose your keybed anchor screws, as I did, I would not recommend just getting new screws and plugging them right in. The Forte chassis/case is aluminum, and even though it's very solid when everything is screwed together, the loss of some key screws will allow the case to flex ever-so-slightly if you put any torque on it. That was my problem -- I replaced the keybed screws with the board just rocked up on its rear edge, and that was torqueing the case just enough that the keybed was not aligning properly to its mount, inside the case.
Unbuttoning the whole case, laying everything out flat and horizontal to get the "wrinkles" out, then realigning the keybed and its mounting holes made all the difference. The trick was to *not* rock the case up on end to reinstall the screws. Inconvenient, obviously, since the screws are on the bottom of the case, but I just dragged each end of the board off the edge of my work table and installed them from underneath (adding lock-washers this time), making sure the keybed stayed aligned and didn't flex. Once the keybed was back where it needed to be (and we're talking just millimeters of difference), I replaced the perimeter screws by the same method.
Like magic, the keybed came back to life; no sticking, no clacking, softly bottoming out -- everything back to normal. So, lesson learned: don't try to work on this board with it propped up on your knees, or on the back of your tailgate. If you lose integrity of the chassis, take it apart, relax all the torque, realign everything, and reinsert the screws while it's sitting flat in "playing position".