Unknown Model Numbers of missing parts

Hello,

I have a Sony Hi Fi audio System from 80`s (probably from 1988). Unfortunately it was not complete, there are some missing parts. I know such parts are one graphic equalizer, the amplifier itself, remote controller and of course, speakers. However I tried to find their respective models without result. The most important information is the model of the amplifier because it provides power and control for most modules.

I own only the following parts:

1.- ST 707RM

FM STEREO/ FM-AM TUNER

2.- CDP-S107

COMPACT DISC PLAYER

3.- TC-WR808M

STEREO CASSETTE DECK

Any information about the models of missing parts (where I can find / buy it) will be very helpful.

Thanks.