Another IC I Can't Identify

[Tony Duell]

On Sun, Nov 11, 2018 at 6:32 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
>
> I am still working on the causes of a Reset on my Pro 350. One 8-pin DIP
> chip that I have traced to is marked as follows:
>
>
>
> 9643TC-B1
>
> F 8313
>
> KOREA
>
>
>
> It is very close to the F-11 chips at the bottom left and marked E135 in
> this picture
> https://rjarratt.files.wordpress.com/2018/10/system-board-labelled.jpg

How about a Fairchild 9643TC dual TTL-MOS level shifter?

I found a datasheet with Google. The pinout seems to be :
1 : Input A
2 : Enable Input
3 : Input B
4 : Ground
5 : Output B
6 : Vcc2 (Output stage Vcc)
7 : Output A
8 : Vcc1 (Input stage Vcc, normally +5V)

-tony