OP hangs using Faytech display

[agv]

Can you please test these comands in a terminal:
sudo rm edid.dat
tvservice -d edid.dat
edidparser edid.dat
tvservice -n

please paste the output of the "edidparser edid.dat" and "tvservice -n" here.

(The quick&dirty solution is delete all lines from the file /home/pi/.config/openplotter/display800x480.py)

Thanks. I tried to test these commands, but with the Faytech display the command 

tvservice -d edid.dat

does not give a response. After ctrl-z the edidparser command gives the message that it failed to open the file edid.dat.
I checked these commands with an other hdmi-display (at home) connected to the same Pi. Then the command (tvservice -d edid.dat) is executed and the file can be parsed. So tvservice does work, but with the Faytech display tvservice does not result in an edid.dat file.
I would be grateful for any suggestion. For the moment I will wait with trying the quick and dirty solution (deleting all lines from the 800x400.py script).
Andries