Macintosh LCII failure

Hi, I recently got an LCII that wouldn't boot. I recapped the power supply, and after that, the LCII powered on, but there was no chime, and the screen was just a blank image.

After that, I recapped the motherboard (just the electrolytic capacitors), but nothing changed. I've tried changing the RAM, the VRAM, removing the hard drive, the floppy drive... and nothing works. If, after turning it on and seeing the blank screen, I quickly turn it off and on again, it doesn't even show the blank screen anymore. I have to turn it off for a few seconds and then turn it on for it to display anything.

Is this a known problem? Does anyone have any idea what could be wrong? The motherboard doesn't seem to have any capacitor damage. I've cleaned everything thoroughly to rule it out, and it still doesn't work.

I did another test. I was testing it with a dead battery (0.5V), and I tested it with a new battery (3.5V), and with both I get the same result, but if I remove the battery, I hear the chime of death. I put any battery back in and I don't hear it. The screen is always blank. Even removing the VRAM shows a blank screen.