With the cash from his mother, he bought a couple of plastic molding machines and started making channel-changing knobs for black-and-white televisions.

带着从母亲处借来的现金，他买下了一套塑料成型机，开始制作用于黑白电视机转换频道的旋钮。

youdao

The red, green and blue components of the signal are fed into three separate high-definition cathode-ray tubes (in effect, fancy black-and-white televisions).

ECONOMIST: Curtains for celluloid

Reports on the number of homes with televisions are impressive, but 75% of India's sets are black and white and are capable of carrying only 14 channels.

CNN: ASIA'S NO PUSHOVER