George W. S Kennesaw , GA October 08, 2016 Appliance: Whirlpool Microwave Hood Combo WMH75520AS0 Several keys on the touchpad unexpectedly stopped working (ie start cancel setup vent fan light cook reheat soften/melt & defrost quick defrost) After extremely poor support from WhirlpooI and researching numerous U-Tube videos, I fully troubleshot potential failed components and connections. All appeared to function properly, so I reassembled the unit and experienced the same problem as before. I then narrowed down the problem to either the Touchpad ($57+$8 shipping) or the control board ($295+shipping). If those did not work, then a new Microwave of better quality, reliability and support than original microwave, Unfortunately, the original manufacturers quality and support has suffered tremendously over the past several years. I finally purchased the Touchboard from Appliance Parts Pro (Tiffany) for $57 because of their 365 day unconditional return policy, part price and knowable service personnel. They even emailed me the wiring diagram & detailed troubleshooting document (which the OEM would not share with me). I received the part in less than 24-hours, reinstalled it, did a final check, plugged it back in and the microwave worked like new. After the repair was completed, I took apart the touchpad to see what caused the malfunction and concluded it was either 1) a misaligned ribbon cable connecting the touchpad to the control board connector, causing it to tear, or 2) a non-functioning button on the touchpad, causing an open circuit to the ribbon cable. Wife was so pleased that she gave me a big hug and tells all our neighbors I can fix their microwaves :) PS...Be very safe by wearing rubber sole shoes, unplug MW, and discharge stored electricity in the MW capacitor before you start troubleshooting or disconnecting/reconnecting components ! The consequences can be shocking, causing injury and/or failure of additional components. Read More... 40 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 2+ hours Tools: Pliers, Screwdrivers