I've had the GTP 1350 for about a year-and-a-half now.
---First of all did you buy your GTP 1350 new or used??
Without going out to my garage to see my detector, when you hit the
MENU button I think the screen goes blank with the exception of the five
modes on the left side of the screen: COINS, JEWELRY, RELICS,
ZERO, or CUSTOM.
Hit the MENU button again and the SENSITIVITY setting then shows on the
screen.........
If none of this is working I would pull the batteries and make absolutely sure
that the eight batteries were placed in their brackets correctly (+'s and -'s in
the correct position). Then place the brackets back in and make sure the
RIVETS on the brackets are facing closest to the center. Turn the POWER
ON and wait a couple seconds.......now hold the POWER button 10 seconds
or until the detector beeps twice to 'reboot' the detector.
After you turn it back on and if it still isn't working then I would send it in for
repair.