Re: MC14489B interfacing

however all I am getting is intermittent operation.

Intermittent operation is normally a symptom of poor decoupling:-

ignore this topic, problem solved.

It is good for future users searching this archive if the original post is not removed and if the solution is posted.

There may be other people interested in what the solution was, also it helps people like me to know what sorts of mistakes can be made so that can be a consideration when tackling other's problems.

The solution: when trying to drive 40 leds, remember to plug in a big(er) power supply.

Thanks. ;)