garmin 196 black screen

Hi,
I own a garmin 196 since 2004. It has worked up to 6 months ago (latest firmware 4.10). Up to yesterday I left the device at home without batteries.
Yesterday I tried to switch on the device (with new batteries in) and nothing happens, only a black screen (all pixels on).
Then I tried to upgrade the firmware to 4.40 and reloaded the maps. The upgrade was successful but the result is the same a black screen.

There exists a kind of 'hard reset'? I tried the one of 296 but without success...

Is this device so delicate that it is broken only being in a drawer
there is somebody that can help me?

Are you SURE the batteries are in correctly? Double check.

The same thing happened to me on the edge of tampa's airspace a few years back on my 295. I thought it was broke. The contrast somehow went down to black. After a few fitful hours on the ground I took it into a dark room and could tell that the screen was working and had to adjust the contrast up until it was visible. I could not see anything under low or normal lighting, it had to be dark. Don't know if that would help but a possible cure.