Nick, which input in the back of the 33 do you use? Tape or radio?

I'm defintiely confused. I just connected the cdp to the radio 1 input. With the stero button in the sound is weak. With the two mono buttons in the sound is strong and full, but in mono obviously, with particular bits of the music buried. So, it's not as I want it, but it's pointing in the right direction. It would seem to me from this that the stereo function is off in some way.
Also, when I put the lead in the radio 2 button and pressed the stereo and mono buttons in a random way (I was getting confused) the Quad light came on. But, I got very little sound and when I pressed more buttons, the Quad light went off.
So the Quad light works, but only when a mysterious sequence of buttons are pressed.
Sound comes out loud and strong, but not when the tape input is used, or when teh stereo button is pressed in.

Does this shed any further light on anything??