Cable barrel adjuster stuck.....

[ratrodtrikes44]

Chain is broke on gear adjuster...barrel will not screw off to replace. When I turn barrel the whole cable turns with it.
Trying not to break as I don't want to replace cable.......Don't know if I should try and hold cable and force it......
It is an old 3 speed twist grip...looks like it would not be fun to replace. '66 Hi Way Patrol by Columbia.

 

[twojs.bike]

Hit it with some PB Blaster and try again in 24 hours. I’ve been using the same can of PB Blaster for 20 years. Amazing stuff and a little goes a long way.

 

[RustySprockets]

Give lube a go. If that doesn't work, you're replacing the chain and rod anyway, so I'd cut the chain to detach it from the cable. Then, you can work on each half as a separate problem--i.e. grasp the barrel and twist the partial chain out.