Hello everyone!

I have 6000CD Player, which responds to only ON/OFF button and volume control. None of the other buttons do any job, including ones on steering wheel. Seemingly, it started malfunction during the February, on those cold days, when car saloon was cold, buttons did not work properly, warms up, everything was fine. Now, completely dead buttons.
I had disc stuck inside, and the same disc kept playing for last two months. Today took it apart, pulled disc out, inspected boards, nothing obvious, everything looks fine. Put everything together with the hope that it will work, but the same problem. Now I can not even enter the Code.
Any advise, help will be greatly appreciated.