Years ago, got a 100 watt stereo receiver/amplifier that wouldn't play, guy didn't want it anymore. Oddly enough, if you turned the volume way up you could faintly hear the audio coming from the large power amplifier IC. Had the thing open, happened to tilt it a certain way, and CLICK, the speakers played for a moment. Bad solder joint on the relay that protects the speakers during power up. Ten seconds with the soldering iron, and it's good as new. Just got a wine cooler (small thermoelectric refrigerator) that was new in the box, never opened, but was 13 years old. Somebody received it as a gift, never used it, and asked if I wanted it. Powered up, but the display just flickered, the fans made little jerks, and I could hear chirping from a switching supply that wouldn't start. The manufacturer didn't have replacement boards for the switcher, but some Googling turned up that this model had frequent problems with bad electrolytics in the power supply, and found people had the exact same failure mode. Youtube turned up somebody showing a bulging cap on the supply, the same symptoms, and replacing it fixed it. Sure enough, the exact same cap on this one is visibly bulging. New one on the way, but I'm pretty confident it will fix it.