Similar to HP 46 ??

[Katie Wasserman]

(03-27-2015 04:44 PM)nn7d@msn.com Wrote:  I have decided that the printer itself is OK. The print drum spins. I can cause the paper to advance. I can raise the two color print ribbon. I can selectively operate all of the hammers. I know that the calculator functions normally in the display mode. Each of the printer functions mentioned above is preceded by what looks like RCA TTL logic circuits 1820-0946. I am searching for a data sheet for this chip which one source identified as a positive NOR gate. After I find the pin-out for this chip, I can check the inputs and outputs to see why it is not activating the transistor drivers for the hammers. Since all printer functions are affected, I suspect an over-all inhibit input which could even be coming from the keyboard printer on/off switch. But, I've got to work my way back systematically.

According to this source it's a CD4001, CMOS quad 2-input NOR gate.