Batboard

Hi I have a R2410A it has batteries installed. But they need replaced. We just replaced batteries in my buddies R2200 and it reads 14.4V now before it read something like 13.2V with the old batteries in it. . My R2410A reads 00V on the lcd display. If i check it with a VOM meter at the battery terminals with the battery unplugged it reads 14.2V. I tried his old batteries to see if it would read any voltage on the display as his did but it reads 00V with those hooked up. I have an operators manual and a R2200A service manual. Nervous because everything works just no battery voltage shown. I tried the rocker switch on the rear and it's in the correct position.

Could someone point me in the right direction to figure out why the display doesn't display the voltage.
Thanks for any help.

rear fuse F2

Tks that was a place I never thought to look as it had 14 volts at battery. the fuse is missing. Have to get some this week.
Guess you loose it at 70 something. But still like to play with the radios. THANKS