Touch screen does not function properly - KitchenAid KHMS2050SSS Microwave Oven

I being an experienced technician all I do is get micro buttons such as used in television set .I carefully apply minimal hot air from a hair dyer to the touch panel in a clean environment then strip the adhesive touch panel to check the wire ring that tress back to the pcb that is just beneath the touch panel. yo have to locate common and the wire responsible for touch, then drill a small hole where the micro button will sit solder to wires on the button then carefully solder them on the board.now make sure the button is on the same level with the surface before you return the adhesive touch panel make sure the button sits well then from beneath apply hot glue please don't use super glue if you don't understand I will send you pictures.

You probably either have a bad connection between the touch pad and the main circuit board, or a component failure on the main circuit board.

Whenever I come across something like this, I always check the door switches for proper operation. Some ovens will not program if they have a switch failure.

Unless it's a door switch, or something else that's inexpensive to fix, I would suggest buying a new oven. 17 years old is quite old. Even if not used much, some components will fail simply due to age.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

If by "touchpad" you mean the touch screen (LCD assembly), those and their connecting strips are very fragile.
If the screen is not lighting after reinstallation, I would first check to be sure the white 3-wire cable is properly plugged back into the lower power board.
If it is, and everything is connected correctly, then you may have received a defective touch screen (LCD assembly) and would need to return it for replacement.
Again, these units are very delicate and the connectors are finicky.
I have an unedited video that shows you how to remove the LCD assembly. It would be useful in reassembly as well.
It is here:
http://www.microwavedisplay.com/lcd_assembly_removal.avi

have you tried reset

HELLO.

The code on the screen indicate electric panel fault resulting from the touchpad malfunction.

The touch pad on your microwave oven acts as the brain of the appliance. It not only contains the buttons that you use to enter cooking settings and times, but also controls the function of the entire microwave. If the touch pad malfunctions or breaks completely, the microwave will cease to function. In this instance, the broken touch pad must be removed and a new touch pad must be installed, to restore functionality to the microwave.

1 Unplug the microwave from the wall outlet.
2 Remove the two screws, located on the front or top of the grill at the top of the microwave.
3 Pull the grill off of the microwave.
4 Remove the mounting screw from the top of the control panel.
5 Lift the control panel up and out to loosen. Look behind the control panel to ensure there are no metal tabs securing the control panel in place. If there are metal tabs, gently rotate the control panel to free the tabs.
6 Transfer the wires from the old control panel to the new control panel one at a time to ensure that the wires are properly installed.
7 Install the new control panel into the microwave and secure using the mounting screw that was removed.
8 Replace the grill from the top of the microwave and secure it using the screws that were removed.
9 Plug the microwave back into the wall outlet.
Thanks.

You can get that repaired for $39.95 in most cases (details here) or order a control / display unit here.
You can also download the owner's manual from the page at the second link.

It's a power save function. You can adjust it. If it's a pc go to "contol panel". There will be help there.

You must remove the vinyl cover from the control panel and wipe down the face underneath it with denatured alcohol. It's pretty tricky depending on your mechanical caliber.
Then clean the inner side of the vinyl cover the same way. Caution don't soak the power unit just dampen a cloth, this goes for the cover also!

We repair these for customers nationwide with our guaranteed $39.95 service.

Feel free to contact me directly.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

William E. Miller
[email protected]
http://www.microwavedisplay.com

It may be a glitch that can be corrected by a hard reset. Unplug it from the power line for a minute, plug it back in, set the clock, then try again.

It may have gotten moisture, contamination, or grease inside, which can happen if one cooks on the stove top without having the microwave's hood vent fan on.

It may simply need repair.

We repair microwave control units and touch panels / touch screens for customers nationwide with our guaranteed $39.95 service.

Feel free to contact me directly.

We're happy to help you and we'd appreciate your thoughtful rating of our answer.

William E. Miller
[email protected]
http://www.microwavedisplay.com