You are watching the Keyboard CPU D80C49HC-187 or μPD80C49HC-187 used in Casio HT-6000 synthesizer. The typical symptom of failure in this chip is no sound from the keyboard although you can start rhythms. 

In my HT-6000, before replacing this chip, beside having no sound when pressing keys, I had garbage on the LCD.

I will also send a very clean copy of the service manual. Check my other items - thousands of parts for synthesizers. Contact if you're looking for something.

The shipping cost is included to any part of the world (registered tracked mail).

I can provide you many D80C48 and D80C49 processors for synthesizers - contact if you're looking for something.