I believe the model number is LDF6920ST. I cannot find the serial number as I have yet to remove the unit from under the cabinet to get at its right side. Since the original post I have purchased a display board. Today when I attempted to plug in the new display board I accidentally reconnected the original display board to the new main board. At first I got nothing and was discouraged because usually this model can be turned on even if the door is unlatched (it has a top view display panel which is hidden when the door is closed). So as last attempt, I closed the latching mechanism to the locked position tripping both toggle switches. The classic chime went on and I got excited. I then opened the door and assumed the latching mechanism needed to be closed at least for the initial program to work. Put the cover and door back together and closed it again and this time nothing happened.
I'm back to square one. I retested incoming power from the whit plug and now I'm not getting 120 which I know I was getting before. Checked for any frayed wires underneath the bend of the door and throughout. Did not find anything. Using a meter at the white plug end, I'm getting 120 to ground but when I meter to the black and white wire directly on the plug I'm getting only 36-40v. I'm assuming the power to come in directly from the bottom to the white plug end. Where am I losing voltage?? Or is there something in between? Does the 120 go to the noise filter and come into the main board at 36-40 volts? Is there some step down transformer between the incoming AC and the white plug which goes to the main board? HELP! I'm already into about $225.00 and to make matters worse after all this I noticed I used the original display board possibly frying the main board again. Even so, this would not cause the incoming power to be so low as I'm metering it without the main board plugged in. Confused and frustrated.