Kawai Synthesizers

I have just purchased a K1 ii and when switched on it looks all good until you
play a sound. The sound is either a mixture of sounds that sustain or crackle
and are a mixture of different sounds that either go up or down in pitch or are
like a LFO has gone crazy but don't respond to the keys pressed. I can change
banks the noise stops but the same behaviour but maybe different sounds. Its as
if the synth has a mind of its own. I don't know wether it may be the CPU or
wave Rom or something else. The battery has just been replaced and everything on the
board looks good. I have tried to reload the patches and the synth only took half the download and MidiOx has said memory buffer full.
Could this be a RAM issue which also affects
 the quality of the sounds??
Any suggestions or just throw it away?? The synth is in really
good condition