u/Aggressive_Cloud_705

Hey, I’m very new to the audio repair stuff, as in this is my first attempt. I got this old nad av716 receiver from a colleague along with a pair of Celestion 66 studio monitors, and after replacing the tweeters I had the whole system working great, however the nad has had an issue with turning and staying on that’s gotten worse over time to the point now where surround sound has stopped working and it barely turns on at all. Pressing the M R OFF button before pressing the power button was a workaround I used for a while but that’s stopped working also, and sometimes pressing certain buttons makes the system turn off straight away. From looking online I’ve checked the diodes and resistors near the power connection and they all seem fine, no visible damage or bulging that I can see anywhere, and when testing with a multimeter I got normal readings. I’m just posting here really hoping anyone has some advice because this is a great old amp with a really good sound and I’d hate to waste it