I will be happy to assist you with this question.
To reset the tv,you need to press vol minus on the tv set,until volume reaches zero,then,keep vol minus pressed and press "menu" on the remote(while aiming the remote toward the remote sensor).Keep them both pressed until you get the self diagnose screen.
Wait until you see a chart with some parameters checked OK.
Then you need to unplug the unit.
Plug it back,and turn it on.
Now you have the initial(out of the box) screen.Follow the setup,then check the HDMI inputs.
If they still do not work,then you will need to replace the "A board".
I can help you with the part#,but I need the model# XXXXX this!
I hope this helps,
Thank you ,and have a great day!
Just a quick clarification.
On this model there are two version,TH50PZ700U and TH50PZ700UA.
The A board will be a different part# XXXXX on this version.
Please look on the side of tv,onto the backcover,there is a label where is listed the model# XXXXX serial#.This is a black label with white writing if the tv is "U" version and a white label with black writing if the unit is a "UA" version.
Please double check for me this version#,that I can provide you with the right part# XXXXX the "A board".
Actually on this model,the A board ( as we know the main board) is split in two section,the one with the HDMI inputs on it is the so called "DG" board.
I will check the part numbers for both version for this board and I will post back soon.
Here I am ,as I promised,
The part# XXXXX the DG board is:
I also attach here a picture with board layout inside of TV,that you will identify them easily:
It looks that these are available at "partstore.com"
See link please:
The price on them is very high,but at least now you can make a decision about trying to fix this issue or not.