Panasonic TX-50AX800 HD HDMI ports no signal but on the 4K HDMI limited input

[Samui67]

Hello again,

for getting a spare mainboard for my TX-58AXW804 i made a deal and catched a cheap TX-50AX800 with the same A-board (actually all boards inside are the same)

Unfortunately there is no signal input shown on all HDMI inputs on this TV.
The 4K HDMI input is working but only limited. Means, that only 4K signals are displayed. With all other resolutions eg. 720, 1080, 1366 or 3D Full HD content on this port, coloured vertical lines are shown on the display. All other functions of the TV are ok.

Could it be related to the T-CON board or is it again related to the A-board?

[Samui67]

Re: Panasonic TX-50AX800 HD HDMI ports no signal but on the 4K HDMI limited input

Meanwhile i checked the video signal path. Also replaced the FR Board with the one from the TX-58AWX804 and tried the factory reset procedure several times. No changes.
The service self check procedure is not showing any problem. The status of everything is ok. Really don't know how to go on now.