Hi there and welcome to the forums!

There are quite a few members in Scotland, but I don't know if any are familiar with Dahlgren. If it's a purely electronics logic problem then an electronics tech might be able to assist(?) Any Ham radio clubs near you? You could also try posting the question into FAQ's, Problems & Solutions?

SOYEB from Birmingham has recently posted a message about a Dahlgren which might be of some help, failing that try the Google custom search in the top right of this page.