These are very compact and complex circuitry. I knew the engineers who designed these. Tomlinson Holman was one of them. Good news! Excellent design, and sound. But bad news, these units always, always develop intermittent board connectors, usually have bad capacitors due to age, use, etc. So cost to repair is always about $200. Last unit I sold in truly correct working condition was about $300. My recommendation is to consider getting Japanese HiFi from the 1980s. Pioneer, Marantz, Kenwood, etc. They are better made receivers, more serviceable, lower cost to buy used. Advent 300 are rare and can be OK if serviced carefully. We can repair these machines!