I got a junk camera surveillance component just by 300JPY. Indeed I had no information of it (just only logo "Kumahira") but I eventually got the connection pinout of this tiny CRT monitor.

It is tiny but surely Cathode-Ray-Tube, meaning B voltage should be more than 1000 V. I don't prefer high voltage (my policy is less than plus/minus 15V, if more than that, thet is out of my scope) but careful circuit trace provides which is video-in and which is Vcc....