Casette player problems???

[stormmotor]

I just recently bought a 1993 Q45 and the radio playes just fine. The casset player plays just fine sometimes and then it plays like the tape is antique and very old but that problem happens on and off sometimes it thumps and then sometimes its all faded sound. The tape plays fine in other machines. I cleaned the deck with a cleaning tape and rubbing alcohol.. Does anyone know how to fix this problem or know where I can find a new unit that hopefully plays cds without screwing up the center dash configeration??