Originally Posted by dpalme
I have no idea how to take the regulator apart......
is the check valve the red toggle valve on the bottom of the barbed out line?
A check valve is a one-way valve. It automatically closes when the flow reverses. It has no external parts.
Some regulators come preconfigured with one on the output, some gas manifolds too. Sounds like you didn't have one, may still not have one.
My co2 regulator has a check valve built into the output toggle (quarter turn aka ball) valve. You can also get add-on check valves.