[Al (astral highway)]

Hi everyone, thank you to all who have posted.

I won't reply individually this time, but just to note, it's great for me that I now know how these things work.

The issue, though, is to find out why a false trigger is happening with the existing arrangement. As the equipment is now quite 'elderly' (ie, 11 years old), it may be that a chip has had it or there may be power supply issues.

The manufacturers were really careful to design against cloning or self-maintenance and scrubbed out all the numbering/ lettering on every IC onboard! I've never seen anything like it!