Uploaded June 2026 | Updated September 2026, 3 weeks ago

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Building a ColecoVision homebrew cartridge for Caverns of Titan should have been straightforward. Famous last words. I feel very stupid, but it is what it is...

In this video I build a 32K ColecoVision cartridge from scratch using a 27C256 EPROM, a 74LS21 logic chip and a TL866II programmer, then fit it into a PCBWay shell and make a custom label for Caverns of Titan. The board goes together, the cart looks the part, and then I discover an "problem".

If you're into ColecoVision, retro gaming, homebrew cartridges, EPROM programming, old hardware, soldering and idiocy, this one should be for you.

PCB and 3D printed shell for this build were made by PCBWay:
pcbway.com - Many thanks to them for supporting the channel!

Chapters
00:00 Caverns of Titan build intro
00:33 32K cartridge board and parts
02:11 Testing the 74LS21 logic chip on the TL866II
03:01 Caverns of Titan and Team Pixelboy background
04:13 Programming the 27C256 EPROM
05:39 Soldering the ColecoVision cartridge
07:52 Designing and fitting the label
10:53 Power-on fail and the Super Game Module problem

Credits and links:
- Caverns of Titan - Program and Audio Visual ©2016 José Luis Tur
- ColecoVision version by Óscar Toledo Gutiérrez
- Board project used in this build: Colecovision 32K Cartridge Board by Dave C
- PCBWay Plus project: pcbway.com/project/shareproject/ColecoVision_32K_Cartridge_Board_ff3e2e8c.html

Support the channel:
Patreon: patreon.com/markfixesstuff

#ColecoVision #CavernsOfTitan #RetroGaming