The motherboard to the Bally Professional Arcade (also known as the Astrocade and Home Library Computer), a video game console released in 1978.  The system is powered by a Zilog Z80 processor and is also one of the first consoles to have four controller ports.
<a href="//commons.wikimedia.org/wiki/User:Evan-Amos" title="User:Evan-Amos">Evan-Amos</a>
<span class="int-own-work" lang="en">Own work</span>