Bought a "refurbished" TRS-80 off eBay for $180, and it smoked on the kitchen table in under 4 minutes
The listing said fully tested and working, so I figured $180 plus $35 shipping was fair for a Model III I could clean up and keep. Powered it on for the first time and a thin ribbon of white smoke curled out of the back in maybe 200 seconds, right in front of my wife. Opened it up and found a bulged cap the seller had actually photographed, just hiding in the corner of the last picture where the shadows were dark. I filed a return, fought the shipping charge for 3 weeks, and got $180 back but ate the $35 because "buyer must cover return shipping." Also lost a kitchen table cloth that now smells like burnt electronics and my wife's trust in my hobby. If you're buying old machines online, do you always ask for a pic of the power supply board before you send money?
Fully tested and working" is doing a lot of heavy lifting in that listing. A seller who hides a bulged cap in the dark corner of the last photo knew exactly what they were doing. That is not a mistake, that is a con. The $35 hurts but the smell in your kitchen and your wife giving you the look every time you eye another old machine, that is the real cost. Always make them send pics of the power board before you pay, no exceptions. If they dodge the request, you already have your answer.