Aiwa CS-500
The CS500 is a very rare boombox from Aiwa. It was sold in 1982 and has 4 speakers (10cm center speakers, 9cm outer speakers). According to the service manual, it measures 476mm long, 168mm high, and 160mm deep. Its power output is specified as "more than" 5 watts per channel. The tape deck's wow and flutter rating is less than 0.05% WRMS, which is very good for a boombox. It does not have separate bass and treble; only a Tone knob. But it does have a DSL button (Dynamic Super Loudness). There are also Line In and Line Out jacks. In Japan, this boombox was called the CS-J50. It seems that the CS-J50 has an extra knob for Mic Mixing.
The service manual can be purchased HERE