This is part 4 production starts. Bistable 555 - 8-bit computer clock - part 3. This 7490 clock has been a thorn in my side for a little over 5 years. Previous blog posts for this project: IoT Alarm Clock - Part 4: Case 1 - The First. We carry a massive selection of Hermle clock parts, Kieninger clock parts, quartz clock pendulums, batter clock parts including quartz movements, clock hands, glass, dials, springs, pendulums.