icom 756proII display delay

[iz5dmq]

hello
i read something from the web but its better ask to the experts here.
i have , sometime , a very long delay when i power on my Icom 756proII , expecially when it is off from many days.

usually it turns on after 4-5 seconds , but sometime , the display becomes on after i can heard the audio from the radio.

anyone knows why?
bye
73
iz5dmq