FUJI LP 5900 NOT BOOTING

[Forestyl]

Hello.
My LP 5900 was unable to boot and the LED2 on the panel was off and only the dash was showing on the LCD. I noticed that rhe D+12V was absent. We fixed it but the machine kept showing the dash sign with the two LEDs 1 and 2 light on the panel.
I then decided to change the GPR23 Board and the machine aaaworked properly.
Now after I reassembled the machine, it showed all the 8 dots then beeped as usual. But at this level, the LCD is now showing a big dot on the LCD as you can see on the attached picture; the dot is blinking.
In this condition, I need assistance.
What can be this big blinking dot on the LCD?
Thank you