The CBM-II Clock board Page

Introduction

Welcome to the CBM-II Clock Page! The CBM-II machines have a special power supply that also supplies either a 50 or 60 Hertz signal to the CBM-II motherboard in order to feed the Time-of-Day (TOD) clock. If your power supply fails and you can't find another you can use standard power supplies, like those from Meanwell but they won't have the proper TOD clock. This board is a simple 555 timer chip circuit and PCB to generate the clock signal that you need. It is small so should mount in any convenient place depending on your power supply size and whether you have an LP or HP machine. .

Information

Dave McMurtrie asked me to create this board for him, based on a clock circuit provided by Michel Pleban. I only created the PCB. I am releasing the design so anyone can use it. You can send the gerbers to any board house you like. I usually use JLCPCB and a batch of 5 PCB's with shipping should be under $10. Parts to build the board should only be a couple dollars. .

Status

I created gerbers for Dave and he submitted them to JLCPCB. The boards arrived and he also sent me a couple. Dave will be building up one for his machine and I hope to build one up to test at some point. I will add pictures and more info at that time.

Github