💾 How to Replace a Failed 6530 in a Commodore IEEE Disk Drive

This week I test out my solution for a failed 6530 in a Commodore IEEE-488 disk drive - and it works!

The 6530 is a factory mask programmed chip that provides RAM, ROM, IO and Timer (RRIOT) functionality. Unlike its sibling the 6532, it’s a custom part specifically for these disk drives due to the ROM image and behaviour of the chip select pins. Finding an original replacement (part #901466) is nearly impossible.

My solution repurposes a 6532 (still available), 74LS02 (quad NOR gate) and 27 series EPROM to replicate the original 6530 functionality.

Need one of these boards? Available at: https://piers.rocks/u/dd6530

A shout out to Ruud Baltissen, who’s efforts here inspired my own: http://baltissen.org/newhtm/6530repl.htm

⏱️ Timestamps
00:00 🚀 Introduction
00:19 📟 RIOT/RRIOT IC overview
01:09 📋 6532/6530 pinout comparison
04:13 📝 6530 replacement schematic
05:40 🔄 6530 replacement PCB layout
06:23 💡 6530 replacement in the flesh
07:09 🧪 First test
09:16 🎉 It verks!
10:46 💭 Final thoughts