Maybe they are OTP? Dwight ________________________________ From: cctech <cctech-boun...@classiccmp.org> on behalf of Wouter de Waal via cctech <cct...@classiccmp.org> Sent: Thursday, October 10, 2019 5:33 AM To: cct...@classiccmp.org <cct...@classiccmp.org> Subject: Re: Mystery chip SCM44506L
> >Very likely a semi custom or custom memory device, due to the prefix. Armed with that and the fact that pin 1 connects to the leadframe I figured maybe it's something like the 6830 Mikbug prom -- 0V on 1, 5V on 12, data on the left, address on the right. Tried reading it like that (for all 16 combinations of chip selects) but 0xFF throughout. So I popped the lid, stuck it under a microscope. The chip says "MCM6816" which is in fact a 1k ROM. Anyone have more information on the 6816 ROM? Thanks W