I had problems with my digital clock display working intermittently on my 2000 Camry LE. For a while I could tap it and it would work for a few minutes but it finally just gave out. After some testing I found that there some bad solder joints had developed that were easily fixed. My clock now works like new. If you have a soldering iron and are comfortable using it, this is an easy fix.
Here's what you need to do.
1) Remove the bezel surrounding the instrument cluster. To do this unscrew the two screws on the underside of the top of the bezel. Then gently pry the bezel off with a taped screwdriver. It is in there pretty tight, be forceful but careful.

See Photo - there are tabs on the sides.
2) Unscrew the four screws holding the instrument cluster in and move it to the left side. No need to remove the wiring.
3) Remove the clock by pinching the side tabs ad pushing it back into the dash. I was able to carefully maneuver it out by passing it to the left through the instrument cluster opening. It seems like it won't fit, but if you keep trying different angles, it should eventually go.
4) Unplug the clock and bring it to your soldering station.
5) Remove the front tinted cover by gently prying the 4 tabs holding it in. I actually broke 2 of the 4 tabs but I was able to use electrical tape upon re-assembly and it worked fine.
6) Remove the 2 small screws holding the circuit board in
7) Gently pry the board out
8) On the underside of the board you will see a row of 4 surface mount resistors, see the circled area in the blurrycam pic.
9) Heat up the solder on each side of the 4 resistors to melt and re-flow it.
10) Re-assemble everything and reinstall the clock.