DIP switches off for defaults?

[shmupsrocks]

Is it reliable to set all DIP switches to off to get default settings or do some boards need switches flipped for what is considered default?

[Sumez]

It's often the case, but I have more than a few boards where it's not. I guess that especially goes for older ones.

Honestly, even a lot of the dip switch settings you can find online don't seem to be entirely reliable regarding default/normal difficulty settings (and in the world of competitive arcade games, what is the "canon" difficulty might even be debatable).
I've often found that the best indication you can find is fire up mame and see what it initializes the dips to. It has a nice graphic representation of the actual physical switches.

[Stan]

You can also look for scans of the game's manuals. They often contain the default settings.

[shmupsrocks]

Can you think of a situation where it isn't hardware safe to just flip everything to off and see what happens?

[Sumez]

Dip switches are intended for operators, not mechanics, so that sounds very unlikely.

I guess some games also have a test mode which will tell you if a dip is in a "non-default" position, but those are kinda rare.