Picture upside down

I assume this set has the power and main board combined as a power board will never make the picture upside down. What happened is you got the wrong board, on element sets you need to order by the small paper sticker number not the board number, you have 2 choices...get the right board or turn the set upside down

maybe you need to change the setting ( model ) from service mode)

Go to service mode and there should be an option to flip the picture, not sure why this should happen when selecting reset as its more common when replacing the main board

If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Reasons for upside down picture are given.

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

Flip the TV over! Just kidding!! When you installed the main board was it identical to the old main board? If so, you might want to look at the old board and ensure there are no jumpers that needed to be set on the new board. Some companies make generic control boards for tvs but have different jumper settings for different models. The jumpers are just little black blocks that connect different pins to each other on top of the circuit board.

Configure Windows "video" properties to have Windows "rotate" the picture 180 degrees, i.e., make Windows produce "upside-down" output, and the screen will "flip" that output.

Check that the connectors are properly put on. In some models of TV sets the connectors are not keyed, and can be inserted in either direction. This would be obviously the connector that is carrying the image data to the screen.

If this is not a reversed connector, then it is most likely a firmware issue in the new replacement board. Make sure the replacement board is the exact one required for your model type.

I would suspect main board more than one you replaced--not likely to get help as Thompson is not known for that--possible firmware upgrade seems likely.

On every set I have seen with upside down/inverted or reversed screen etc it has been either a firmware issue or a main board.

Check in the setting of your webcameras control panel and see if there is an option for changing the view.