Nikon FG exposure

Trying out this camera withe 50mm f/1.8 series E. Two LEDs illuminate and blink at 125 and 60 when I half press the shutter button, but no matter what I do I can’t get any change of positions of these LEDs when I adjust the shutter speed or aperture, or set the camera to A or P. The LEDs stay at 60 and 125. I don’t know anything about Nikon cameras and I read the manual but I can’t figure out what I’m doing wrong. Any suggestions?

Did you set the lens aperture to its smallest setting? For example, f22. The FG will choose the aperture and shutter speed when in P mode, and the shutter speed when in A mode. But the lens aperture must be set on the smallest f stop for the P mode. When the LEDs show 60 and 125, the camera has chosen a shutter speed somewhere in between those two speeds in relation to the chosen aperture.

Wherever I set the aperture, the LEDs stay on 60 and 125 and blink like it's doing a battery check. Even in manual, adjusting the shutter speed or aperture makes no difference - the LEDs continue to blink on 60 and 125.

Advance the film (or even without film) a few frame to get the frame count to 1 or above. Before frame 1 the 60 and 120 LED will blink and the meter doesn't work. In this condition the shutter will fire at the flash sync speed which is 1/90 (that's why the 60 and 120 led blink because the shutter speed chosen is between these 2)