Internet forums and the amazing book about fixing classic Macs - Macintosh Repair and Upgrade Secrets - suggested that the black screen is often a symptom of the cold joints in J4 connector. I hoped that it’ll be enough to turn the brightness knob, but it wasn’t the case. So, the first thing to fix was the screen. The worst case scenario - I’ll get a modern art sculpture. However, the low cost was justified - according to the description, the screen was dead, it also lacked of the mouse and the keyboard. That’s why I was really happy to find a Macintosh Plus in an attractive price. Sometimes you may find something on the local auction portal, but usually it costs a lot.
Unfortunately, they are not so common in Europe as in the US and the costs of the shipment are often higher than the computer itself.
I wanted to extend my vintage computer collection with a classic, all-in-one Macintosh for a long time.