I'm wondering if the plug pinout setup arrangment is similar to the old Zenith 9" Portable Color sets from the 1980s where you had an AC Plug that had a large plug that plugged into the back of the TV and jumpered the 12VDC pins and plugged directly into the AC Pins to allow it to run on AC Voltage and then had a Car Adaptor that jumpered the AC pins and then plugged directly into the 12VDC pins and ran the TV on 12VDC for use in a car.
