Powers up but only cd function and volume function works manually

I worked in a Sony warranty center for years...these units had a manufacturing problem that would cause many problems to arise...the grounds inside the unit would not make proper connection and cause all sorts of problems...this sounds like it may be the problem, of course there may be other causes too...simply put, if you know how to solder, then you can try to fix the unit yourself...you need to find the grounding screws that ground the circuits inside, then you will need some pieces of wire to "bond" all of the grounding points together. If that does not solve the problem, then the problem may be either in the switching IC or possibly the microprocessor...If the microprocessor is bad then I wouldn't even consider fixing as the cost of a microprocessor is veery high