It is a YAMAHA pre-main amplifier CA-X1.
I have confirmed sound output except for the phono input. Since there is some change in the sound, I think each knob is also working.
※ The TREBLE knob may sometimes spin freely, but it operates normally when pressed slightly.

As it is old, there may be some scratching or difficulty in operation at times.
The power lamp does not light up, but it is powered on.

As it is very old, please be aware that some maintenance may be necessary.