Using sockets instead of components

[james_s]

Why do you want to put the relay in a socket in the first place? Is it an optional part? Sockets add cost and potential failure points, I rarely use them unless it's something like a programmable part that needs to be removed to program it.

[JSanders]

Mechanical relays don’t have the best MTBF rating, so want the ability to swap it out without having to perform major work on the board and to help eliminate any prolonged down time if a failure does occur. And the cost is negligible running $ 0.03 per socket.

[james_s]

Relays are at least as reliable as sockets in my experience, and I wouldn't call replacing a single through-hole component as "major work" but I guess it depends on the application.

[nctnico]

Relays are at least as reliable as sockets in my experience, and I wouldn't call replacing a single through-hole component as "major work" but I guess it depends on the application.

I agree. Well, maybe a socket is even less reliable. Unless you run a relay near the max ratings (also keep in mind the minimum current spec!), they last insanely long.
The only small signal relays I recall replacing where reed relays in an old HP unit because the relays contacts got magnetised and became sticky.

[james_s]

I replaced the relays in the attenuator modules in my TDS700 scope because contact resistance was causing SPC to fail, but that is a special case with a very sensitive circuit. Replacing those was a proper pain in the butt since they're mounted on fragile ceramic boards and you can paint yourself into a corner if you don't install them in just the right order.

[JSanders]

Personally I’ve never had a socket fail – ever, but have experience many relay’s that have needed replacement. As for the effort needed in replacing a soldered component vs one mounted in a socket is night and day.

The boards are to be located inside an enclosure with mounting screws / standoffs and have several wired connections. In order to change out a soldered component, everything must be disconnected, the board un-screwed, removed and taken to a workbench. Heating / wicking or vacuuming the old solder to remove the relay, cleaning the pads in preparation of applying new solder, then the actual installation of the replacement relay.

During this process the board could possibly be damaged, a cold solder joint could ensue and if nothing adverse takes place then the cleaning any flux residue would follow proceeding the re-installation - remounting it into the enclosure and hooking up the wired connections.

With a socket mounted component one need only power down the system, pull the old relay and replace with the new. There’s minimal concern for accidental damage to nearby component and absolutely zero concerns in creating a cold solder joint. There’d be no worries in causing damage to the wired connections as they’d all stay in place as the board wouldn’t have to be removed from it’s enclosure.

Also when dealing with components that have a lower then optimal MTBF, which can be easily replaced, one can justify / entertain the idea of preventative maintenance if desired or if it were deemed a critical system. While that’s not the case here it is something we’ve done in the past which simply wouldn’t be feasible with soldered components.