PS2 keeps crashing after 10 minutes of use

I have a fat ps2 scph30000 that keeps crashing after 10-20 minutes of using it without needing to play a game. I’ve searched various forums to see if anyone else had the same issue and some suggested it was the cmos battery. After taking it apart and replacing the battery turns out that wasn’t the issue, I also saw some other forums that had a similar problem but nobody had an answer. My guess is that the main motherboard chips need to be reflowed or it might be a power supply issue but that’s about as far as I can guess. If I can get help with this issue I’ll be willing to pay shipping and mail.