CASIO fx-4000P scientific calculator from 1986

[jebem]

And as expected, I had to dismantle the machine for cleaning and checking.

This specimen had poor LCD contrast.
The issue was fixed after cleaning the battery holder connection pads on the PCA.







SoC processor: Hitachi HD61747B38 6J 43 (1986 week 43)
Memory: HD61914 8kbit static RAM 6K33 (1986 week 33)
This is the same PCA as used on the FC-200 financial calculator, but using a different firmware.