Thank you to let me in your DiyAudio club

I am 67 years old, living in Montreal, Quebec, Canada and i just a few week ago decide to listing to my old vinyl record with my QUAD 33 an QUAD 303. My QUAD has not been use for the past 20 years. They were bought in 1977 with a hard working summer job. They still work very well, except of the control balance that only give sound on the right channel.
i have to find a new control balance mechanism and may be find some post that would help me find the part and repair

thank you in advance for your help

Jean Derome
 
I think i found the problem on one of the QUAD 303 amp board. Look at the middle board
QUAD 303 board.jpeg