Repairing a LifeFitness Elliptical Board (SM8958AC25P (8052 Derivative))

[Toadlips]

Good evening all,

I'm very much a newbie to electronic circuit troubleshooting, but I'm willing to learn enough to become a comfortable hack.  I have a LifeFitness Elliptical machine, and the console starts acting crazy after it's been on for a few minutes.  By crazy, it "acts" like a key on the membrane keyboard is stuck down because it beeps as if a key were pressed when no keys are being pressed.  It seems like the down arrow is being held down because it flips through the program options.  If I press the up arrow, then the scrolling of the options will stop.

So, my first inclination was to pry the membrane keypad apart and put a piece of plastic over the contact pad for the down arrow, but that had no effect so I removed the plastic pad.  Indeed, when I do a continuity check on the pins coming from the keypad, each key appears to work properly, including the down arrow.  So I'm thinking my problem may be elsewhere.

The service manual says that when the console board starts acting strange, then it's probably the "memory or the clock".  Now, this thing has an SyncMOS SM8958AC25P (8052 derivative) microcontroller, and I had a fantastic idea that I would get a universal programmer for this chip and get the program off of it in case the microcontroller was starting to flake out.  I tried that, but when I read all 32K of memory, it's all zeroes...not "blank", but zeroes.  Does anyone know if that chip somehow prevents the reading of the program?  I "assume" that the program is stored in that flash RAM.

Now, there is one hitch.  Connected to pins 7&8 (SPWM channels), is an EEPROM AT24C02.  Is it possible that that EEPROM is actually holding the program for the microcontroller?  Would the microcontroller "know" to look to that external memory to get its program if there is nothing to tell it to do so in the flash RAM included with the microcontroller?  Also, there is a crystal connected to the clock pins...should I be looking at that?

Yes, I realize that I have two different agendas: 1) just fix the thing and 2) get the program so that I'll be able to repair this thing in the future if the microcontroller gets fried...if it's possible

Thanks for any pointers!