No screen and no sound

I've had this particular game boy for about 3 or 4 years. It worked fine until now but then it just stopped working. The red LED turns on but there is no sound and no image on the screen.

I decided to take it apart and clean it. I put it back together and... Nothing. I left it sitting a couple of hours and decided to try again. This time the screen turned on normally. I was relieved but decided to unplug and replug the top board just in case to see if it would still work. It didn't. I had no sound and no image again.

At first I thought a cap blew. I checked all of them and saw that none of them look bad (I can't check them since I don't own a multimeter). Is it even possible that a cap would be faulty if the screen turned on when I tried but then stopped working again?