[WarOnPrivacy]

I haven't seen a tube deployment like that before - where the tube is combined with it's supporting components into one module - and that module plugs into a tube socket.

It's clever. It should reduce time for some repairs.

[Gibbon1]

If they're the same you can swap them and see if the problem changes. Otherwise swap in known good ones till to works.

Old bus based systems you did that too. I remember once sending a dozen cards to a customer who had an intermittent issue.