Thanks, but it does not help finding any info yet.
The chip says B6000EA 8006
It is a 40 pin 1/20 inch spaced 4-bit microcontroller from 1976.

I realize this thread is 2 1/2 years dead, but that chip is in the same family as the chips used in the Mattel handheld LED games like Battlestar Galactica Space Alert (B6001EA) and Football (B6100EB).  I've decapped those chips and taken die shots with hopes of getting them emulated in MESS, but have been unable to find any documentation on the CPUs.  I visually transcribed the ROM bits from Battlestar Galactica, but without knowing the opcodes, it's tough to go any further.  It's possible that your B6000 was used in another handheld game or a calculator.